[1] Why Earth is called the blue planet?
A.
Because of two-thirds surface covered by water
B.
Because of water laden clouds in the atmosphere
C.
Because of pollution in the atmosphere
D.
None of these
Ans:
Because of two-thirds surface covered by water
Explanation :
Earth is called the blue planet because two-thirds of its surface is covered by water.
[2] The density of a gas is maximum at –
A.
Low temperature, low pressure
B.
Low temperature, high pressure
C.
High temperature, low pressure
D.
High temperature, high pressure
Ans:
Low temperature, high pressure
Explanation :
The density of gases depends upon the temperature. The higher the temperature, the more the molecules are spread out and the lower the density. The result is that warm gases rise and cool gases sink.
[3] A person standing on a railway platform listens to the whistles of arriving and departing trains. The whistle heard is -
A.
the same in both cases in all respects
B.
of higher intensity when train arrives
C.
of higher pitch when train arrives
D.
of higher pitch when train departs
Ans:
of higher pitch when train arrives
Explanation :
0
[4] The cause for the Tsunami, as deduced by the seismologists, is –
A.
Gravitational pull of the moon
B.
Low pressure trough in the ocean
C.
Deformation of sea floor and vertical displacement of water
D.
Sudden change in the monsoon wind
Ans:
Deformation of sea floor and vertical displacement of water
Explanation :
Earthquakes, volcanic eruptions and other underwater explosions (including detonations of underwater nuclear devices), landslides, glacier calvings, meteorite impacts and other disturbances above or below water all have the potential to generate a tsunami. Tsunami can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Tectonic earthquakes are a particular kind of earthquake that are associated with the Earth's crustal deformation; when these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position.
[5] Should cars have bumpers that collapse under impact?
A.
Yes, since the offending car should get damaged and pay for the mistake
B.
No, since it would be very expensive to get the car repaired
C.
No, since the colliding car would then ram into the occupants and kill them
D.
Yes, since they help to absorb the impact of a collision and keep the occupants safe
Ans:
Yes, since they help to absorb the impact of a collision and keep the occupants safe
Explanation :
In automobiles, a bumper is the front-most or rear-most part., ostensibly designed to allow the car to sustain an impact without damage to the vehicle's safety systems. They are not capable of reducing injury to vehicle occupants in high-speed impacts, but are increasingly being designed to mitigate injury to pedestrians struck by cars.
[6] Light houses are places with powerful lights to :
A.
guide and resolve traffic jams in crowded metrocities during nights.
B.
guide and help large crowds at religious gathering during nights.
C.
indicate to the incoming warships, the location of a harbour during night.
D.
guide and warn the ships coming from different directions in the ocean.
Ans:
guide and warn the ships coming from different directions in the ocean.
Explanation :
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses and used as an aid to navigation for maritime pilots at sea or on inland waterways. Lighthouses mark dangerous coastlines, hazardous shoals, reefs, safe entries to harbors, and can also assist in aerial navigation.
[7] A bird sitting on a high tension electric wire does not get electrocuted because –
A.
it has high resistance
B.
the body is earthed
C.
it does not form a closed path for the flow of current
D.
its feet are good insulators
Ans:
it does not form a closed path for the flow of current
Explanation :
Electricity travels from a place of high voltage to low voltage, just as water travels from high elevation to low elevation. A bird, or any living thing, that touches a wire (where electricity is moving from high voltage to low voltage) and also touches the ground (a place with no voltage) creates a path that allows the electricity to travel through that body and into the place with no voltage. When electricity travels through a body in this fashion, electrocution takes place, and the bird can die.
[8] A vacuum cleaner works on the principle of pressure difference. On the moon it will –
A.
work as efficiently as on the earth
B.
not work at all
C.
work with reduced efficiency
D.
work with increased efficiency
Ans:
not work at all
Explanation :
Vacuum cleaners work by creating a lower pressure just inside the opening which touches the floor. By creating a low pressure inside the machine, higher air pressure in the room pushes its way into the vacuum cleaner, taking the dirt with it.
[9] The propagation of sound waves in a gas involves –
A.
Adiabatic compression and rarefaction
B.
Isothermal compression and rarefaction
C.
Isochoric compression and rarefaction
D.
Isobaric compression and rarefaction
Ans:
Adiabatic compression and rarefaction
Explanation :
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing. During propagation, waves can be reflected, refracted, or attenuated by the medium. Sound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves.
[10] When a body is taken from earth to moon –
A.
Mass changes but weight remains same
B.
Weight changes but mass remains same
C.
Both weight and mass change
D.
Both weight and mass re-main same
Ans:
Weight changes but mass remains same
Explanation :
Mass is how much stuff we are made of, and it is the same whether we are on Earth, on the moon, on Mercury, or anywhere else one can think of. We are held on Earth by gravity. Gravity pulling on mass is our weight .
[11] Superconductors are those elements –
A.
Whose conductivity is intermediate between metals and insulators
B.
Whose resistance falls almost to zero at very low temperature
C.
Which conduct electricity only at super-high temperature
D.
Which conduct electricity only, at super-high temperatures
Ans:
Whose resistance falls almost to zero at very low temperature
Explanation :
Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state.
[12] Ail oil drop spreads over water because –
A.
oil is lighter than water
B.
oil is more viscous
C.
oil does not mix with water
D.
surface tension of oil is much smaller than that of water
Ans:
surface tension of oil is much smaller than that of water
Explanation :
Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in the floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects (e.g. water striders) to run on the water surface. This property is caused by cohesion of similar molecules, and is responsible for many of the behaviors of liquids.
[13] The nature of fuse wire is –
A.
high resistance and low melting point.
B.
high resistance and high melting point.
C.
low resistance and high melting point.
D.
low resistance and low melting point.
Ans:
high resistance and low melting point.
Explanation :
A fuse or fusable link works by opening an electrical circuit when the current becomes too high. As the current increases, the temperature of the wire increases. So a fuse wire should have a low melting point and should be connected in series with the appliance. Besides, it should have a comparatively high resistance.
[14] In a railway track, two rails are joined end to end with a gap in between them because –
A.
steel can be saved
B.
accidents due to contraction in winter can be avoided
C.
air-gaps are necessary for bearing the weight of running train
D.
accidents due to expansion in summer can be avoided.
Ans:
accidents due to expansion in summer can be avoided.
Explanation :
The volume of materials changes depending on current temperature. Usually heat makes them expand, and cold leads them to contract. There have to be gaps to avoid strain on the tracks. The same applies in many other fields of engineering, i.e. bridge building.
[15] When a pall of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is –
A.
below a certain minimum value irrespective of amour of water In the pail
B.
above a certain minimum value irrespective of amount of water in the pail
C.
above a certain minimum value depending on amount of water in the pail
D.
below a certain minimum value depending on amount of water in the pail
Ans:
above a certain minimum value irrespective of amount of water in the pail
Explanation :
When a pail of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is great enough. At every point in the circle the water tries to fall vertically out due to the force of gravity g but also tries to move in a straight line due to its circular motion.
[16] Vehicle tyres are inflated properly –
A.
to ensure smooth running.
B.
to allow the vehicle to take more load.
C.
to avoid skidding and to minimize friction
D.
to go fast and save fuel.
Ans:
to avoid skidding and to minimize friction
Explanation :
Under-inflated tyres create more friction with the road, increasing fuel consumption by up to ten per cent and are prone to skidding on either wet or slippery surfaces. Low pressures also lead to premature wear and risk of tyre blowout or bulging.
[17] Refrigeration is a process which –
A.
kills bacteria
B.
slows down the bacterial growth
C.
Inactivates the bacteria
D.
Plasmolyses the bacteria
Ans:
slows down the bacterial growth
Explanation :
Bacteria thrive in warm, moist conditions. Refrigeration allows the temperature to be lowered so far that food can be stored for days or even months. Keeping food cold (at or below 4°C) slows down bacterial growth which helps reduce the risk of food borne illness.
[18] The function of ball bearings in a wheel is –
A.
to increase friction
B.
to convert kinetic friction into rolling friction
C.
to convert static friction into kinetic friction
D.
just for convenience
Ans:
to convert kinetic friction into rolling friction
Explanation :
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
[19] Which of the following is not a property of heavy water?
A.
Boiling point of heavy water is lower than that or ordinary water
B.
Density of heavy water is higher than that of ordinary water
C.
Freezing point of heavy water is higher than that of ordinary water
D.
It produces corrosion
Ans:
Boiling point of heavy water is lower than that or ordinary water
Explanation :
Heavy water, formally called deuterium oxide or 2H2O or D2O, is a form of water that contains the hydrogen isotope deuterium, rather than the common protium isotope. The colloquial term heavy water is often also used to refer a highly enriched water mixture that contains mostly deuterium oxide but also contains some ordinary water molecules as well: for instance heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction. In comparison, in ordinary water, there are only about 156 deuterium atoms per million hydrogen atoms). In its pure form, it has a density about 11% greater than water, but otherwise, is physically and chemically similar. Heavy water is 10.6% denser than ordinary water, a difference which is not immediately obvious.
[20] A mirage occurs because of –
A.
Reflection by hot ground
B.
Total internal reflection by layers of air
C.
Interference of light
D.
Diffraction of light
Ans:
Total internal reflection by layers of air
Explanation :
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and "Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically-stacked images, which form one rapidly-changing mirage. Cold air is denser than warm air and has therefore a greater refractive index.
[21] Knot is a measure of –
A.
The speed of ship
B.
The curvature of spherical objects
C.
Solar radiation
D.
Intensity of earthquake shock
Ans:
The speed of ship
Explanation :
The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. There is no standard abbreviation but km is commonly used. The knot is a non-SI unit accepted for use with the International System of Units (SI).
[22] When the main switch of the house is put off it disconnects the –
A.
live wire only
B.
live wire and the earth wire
C.
live wire and the neutral wire
D.
earth wire and the neutral wire
Ans:
live wire and the neutral wire
Explanation :
Three wires enter most homes from the power pole—two "hot" wires and a third "neutral" wire. Each hot wire provides 120-volt current for conventional lights, receptacles, and appliances when paired with the neutral wire, which is normally kept at zero volts or "ground potential." When both, hot wires are used together with the neutral, they power large 240-volt appliances such as air conditioners and electric ovens. All the electric appliances stop working in a house when the main switch is put off because the electric circuit (the path where the electricity travels) gets opened.
[23] Negative feedback in amplifiers –
A.
increases bandwidth and decreases noise
B.
decreases bandwidth and decreases noise
C.
increases bandwidth and increases noise
D.
decreases bandwidth and increases noise
Ans:
increases bandwidth and decreases noise
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
Earth is called the blue planet because two-thirds of its surface is covered by water.
[2] The density of a gas is maximum at –
A.
Low temperature, low pressure
B.
Low temperature, high pressure
C.
High temperature, low pressure
D.
High temperature, high pressure
Ans:
Low temperature, high pressure
Explanation :
The density of gases depends upon the temperature. The higher the temperature, the more the molecules are spread out and the lower the density. The result is that warm gases rise and cool gases sink.
[3] A person standing on a railway platform listens to the whistles of arriving and departing trains. The whistle heard is -
A.
the same in both cases in all respects
B.
of higher intensity when train arrives
C.
of higher pitch when train arrives
D.
of higher pitch when train departs
Ans:
of higher pitch when train arrives
Explanation :
0
[4] The cause for the Tsunami, as deduced by the seismologists, is –
A.
Gravitational pull of the moon
B.
Low pressure trough in the ocean
C.
Deformation of sea floor and vertical displacement of water
D.
Sudden change in the monsoon wind
Ans:
Deformation of sea floor and vertical displacement of water
Explanation :
Earthquakes, volcanic eruptions and other underwater explosions (including detonations of underwater nuclear devices), landslides, glacier calvings, meteorite impacts and other disturbances above or below water all have the potential to generate a tsunami. Tsunami can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Tectonic earthquakes are a particular kind of earthquake that are associated with the Earth's crustal deformation; when these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position.
[5] Should cars have bumpers that collapse under impact?
A.
Yes, since the offending car should get damaged and pay for the mistake
B.
No, since it would be very expensive to get the car repaired
C.
No, since the colliding car would then ram into the occupants and kill them
D.
Yes, since they help to absorb the impact of a collision and keep the occupants safe
Ans:
Yes, since they help to absorb the impact of a collision and keep the occupants safe
Explanation :
In automobiles, a bumper is the front-most or rear-most part., ostensibly designed to allow the car to sustain an impact without damage to the vehicle's safety systems. They are not capable of reducing injury to vehicle occupants in high-speed impacts, but are increasingly being designed to mitigate injury to pedestrians struck by cars.
[6] Light houses are places with powerful lights to :
A.
guide and resolve traffic jams in crowded metrocities during nights.
B.
guide and help large crowds at religious gathering during nights.
C.
indicate to the incoming warships, the location of a harbour during night.
D.
guide and warn the ships coming from different directions in the ocean.
Ans:
guide and warn the ships coming from different directions in the ocean.
Explanation :
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses and used as an aid to navigation for maritime pilots at sea or on inland waterways. Lighthouses mark dangerous coastlines, hazardous shoals, reefs, safe entries to harbors, and can also assist in aerial navigation.
[7] A bird sitting on a high tension electric wire does not get electrocuted because –
A.
it has high resistance
B.
the body is earthed
C.
it does not form a closed path for the flow of current
D.
its feet are good insulators
Ans:
it does not form a closed path for the flow of current
Explanation :
Electricity travels from a place of high voltage to low voltage, just as water travels from high elevation to low elevation. A bird, or any living thing, that touches a wire (where electricity is moving from high voltage to low voltage) and also touches the ground (a place with no voltage) creates a path that allows the electricity to travel through that body and into the place with no voltage. When electricity travels through a body in this fashion, electrocution takes place, and the bird can die.
[8] A vacuum cleaner works on the principle of pressure difference. On the moon it will –
A.
work as efficiently as on the earth
B.
not work at all
C.
work with reduced efficiency
D.
work with increased efficiency
Ans:
not work at all
Explanation :
Vacuum cleaners work by creating a lower pressure just inside the opening which touches the floor. By creating a low pressure inside the machine, higher air pressure in the room pushes its way into the vacuum cleaner, taking the dirt with it.
[9] The propagation of sound waves in a gas involves –
A.
Adiabatic compression and rarefaction
B.
Isothermal compression and rarefaction
C.
Isochoric compression and rarefaction
D.
Isobaric compression and rarefaction
Ans:
Adiabatic compression and rarefaction
Explanation :
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing. During propagation, waves can be reflected, refracted, or attenuated by the medium. Sound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves.
[10] When a body is taken from earth to moon –
A.
Mass changes but weight remains same
B.
Weight changes but mass remains same
C.
Both weight and mass change
D.
Both weight and mass re-main same
Ans:
Weight changes but mass remains same
Explanation :
Mass is how much stuff we are made of, and it is the same whether we are on Earth, on the moon, on Mercury, or anywhere else one can think of. We are held on Earth by gravity. Gravity pulling on mass is our weight .
[11] Superconductors are those elements –
A.
Whose conductivity is intermediate between metals and insulators
B.
Whose resistance falls almost to zero at very low temperature
C.
Which conduct electricity only at super-high temperature
D.
Which conduct electricity only, at super-high temperatures
Ans:
Whose resistance falls almost to zero at very low temperature
Explanation :
Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state.
[12] Ail oil drop spreads over water because –
A.
oil is lighter than water
B.
oil is more viscous
C.
oil does not mix with water
D.
surface tension of oil is much smaller than that of water
Ans:
surface tension of oil is much smaller than that of water
Explanation :
Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in the floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects (e.g. water striders) to run on the water surface. This property is caused by cohesion of similar molecules, and is responsible for many of the behaviors of liquids.
[13] The nature of fuse wire is –
A.
high resistance and low melting point.
B.
high resistance and high melting point.
C.
low resistance and high melting point.
D.
low resistance and low melting point.
Ans:
high resistance and low melting point.
Explanation :
A fuse or fusable link works by opening an electrical circuit when the current becomes too high. As the current increases, the temperature of the wire increases. So a fuse wire should have a low melting point and should be connected in series with the appliance. Besides, it should have a comparatively high resistance.
[14] In a railway track, two rails are joined end to end with a gap in between them because –
A.
steel can be saved
B.
accidents due to contraction in winter can be avoided
C.
air-gaps are necessary for bearing the weight of running train
D.
accidents due to expansion in summer can be avoided.
Ans:
accidents due to expansion in summer can be avoided.
Explanation :
The volume of materials changes depending on current temperature. Usually heat makes them expand, and cold leads them to contract. There have to be gaps to avoid strain on the tracks. The same applies in many other fields of engineering, i.e. bridge building.
[15] When a pall of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is –
A.
below a certain minimum value irrespective of amour of water In the pail
B.
above a certain minimum value irrespective of amount of water in the pail
C.
above a certain minimum value depending on amount of water in the pail
D.
below a certain minimum value depending on amount of water in the pail
Ans:
above a certain minimum value irrespective of amount of water in the pail
Explanation :
When a pail of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is great enough. At every point in the circle the water tries to fall vertically out due to the force of gravity g but also tries to move in a straight line due to its circular motion.
[16] Vehicle tyres are inflated properly –
A.
to ensure smooth running.
B.
to allow the vehicle to take more load.
C.
to avoid skidding and to minimize friction
D.
to go fast and save fuel.
Ans:
to avoid skidding and to minimize friction
Explanation :
Under-inflated tyres create more friction with the road, increasing fuel consumption by up to ten per cent and are prone to skidding on either wet or slippery surfaces. Low pressures also lead to premature wear and risk of tyre blowout or bulging.
[17] Refrigeration is a process which –
A.
kills bacteria
B.
slows down the bacterial growth
C.
Inactivates the bacteria
D.
Plasmolyses the bacteria
Ans:
slows down the bacterial growth
Explanation :
Bacteria thrive in warm, moist conditions. Refrigeration allows the temperature to be lowered so far that food can be stored for days or even months. Keeping food cold (at or below 4°C) slows down bacterial growth which helps reduce the risk of food borne illness.
[18] The function of ball bearings in a wheel is –
A.
to increase friction
B.
to convert kinetic friction into rolling friction
C.
to convert static friction into kinetic friction
D.
just for convenience
Ans:
to convert kinetic friction into rolling friction
Explanation :
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
[19] Which of the following is not a property of heavy water?
A.
Boiling point of heavy water is lower than that or ordinary water
B.
Density of heavy water is higher than that of ordinary water
C.
Freezing point of heavy water is higher than that of ordinary water
D.
It produces corrosion
Ans:
Boiling point of heavy water is lower than that or ordinary water
Explanation :
Heavy water, formally called deuterium oxide or 2H2O or D2O, is a form of water that contains the hydrogen isotope deuterium, rather than the common protium isotope. The colloquial term heavy water is often also used to refer a highly enriched water mixture that contains mostly deuterium oxide but also contains some ordinary water molecules as well: for instance heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction. In comparison, in ordinary water, there are only about 156 deuterium atoms per million hydrogen atoms). In its pure form, it has a density about 11% greater than water, but otherwise, is physically and chemically similar. Heavy water is 10.6% denser than ordinary water, a difference which is not immediately obvious.
[20] A mirage occurs because of –
A.
Reflection by hot ground
B.
Total internal reflection by layers of air
C.
Interference of light
D.
Diffraction of light
Ans:
Total internal reflection by layers of air
Explanation :
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and "Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically-stacked images, which form one rapidly-changing mirage. Cold air is denser than warm air and has therefore a greater refractive index.
[21] Knot is a measure of –
A.
The speed of ship
B.
The curvature of spherical objects
C.
Solar radiation
D.
Intensity of earthquake shock
Ans:
The speed of ship
Explanation :
The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. There is no standard abbreviation but km is commonly used. The knot is a non-SI unit accepted for use with the International System of Units (SI).
[22] When the main switch of the house is put off it disconnects the –
A.
live wire only
B.
live wire and the earth wire
C.
live wire and the neutral wire
D.
earth wire and the neutral wire
Ans:
live wire and the neutral wire
Explanation :
Three wires enter most homes from the power pole—two "hot" wires and a third "neutral" wire. Each hot wire provides 120-volt current for conventional lights, receptacles, and appliances when paired with the neutral wire, which is normally kept at zero volts or "ground potential." When both, hot wires are used together with the neutral, they power large 240-volt appliances such as air conditioners and electric ovens. All the electric appliances stop working in a house when the main switch is put off because the electric circuit (the path where the electricity travels) gets opened.
[23] Negative feedback in amplifiers –
A.
increases bandwidth and decreases noise
B.
decreases bandwidth and decreases noise
C.
increases bandwidth and increases noise
D.
decreases bandwidth and increases noise
Ans:
increases bandwidth and decreases noise
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
0
[4] The cause for the Tsunami, as deduced by the seismologists, is –
A.
Gravitational pull of the moon
B.
Low pressure trough in the ocean
C.
Deformation of sea floor and vertical displacement of water
D.
Sudden change in the monsoon wind
Ans:
Deformation of sea floor and vertical displacement of water
Explanation :
Earthquakes, volcanic eruptions and other underwater explosions (including detonations of underwater nuclear devices), landslides, glacier calvings, meteorite impacts and other disturbances above or below water all have the potential to generate a tsunami. Tsunami can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Tectonic earthquakes are a particular kind of earthquake that are associated with the Earth's crustal deformation; when these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position.
[5] Should cars have bumpers that collapse under impact?
A.
Yes, since the offending car should get damaged and pay for the mistake
B.
No, since it would be very expensive to get the car repaired
C.
No, since the colliding car would then ram into the occupants and kill them
D.
Yes, since they help to absorb the impact of a collision and keep the occupants safe
Ans:
Yes, since they help to absorb the impact of a collision and keep the occupants safe
Explanation :
In automobiles, a bumper is the front-most or rear-most part., ostensibly designed to allow the car to sustain an impact without damage to the vehicle's safety systems. They are not capable of reducing injury to vehicle occupants in high-speed impacts, but are increasingly being designed to mitigate injury to pedestrians struck by cars.
[6] Light houses are places with powerful lights to :
A.
guide and resolve traffic jams in crowded metrocities during nights.
B.
guide and help large crowds at religious gathering during nights.
C.
indicate to the incoming warships, the location of a harbour during night.
D.
guide and warn the ships coming from different directions in the ocean.
Ans:
guide and warn the ships coming from different directions in the ocean.
Explanation :
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses and used as an aid to navigation for maritime pilots at sea or on inland waterways. Lighthouses mark dangerous coastlines, hazardous shoals, reefs, safe entries to harbors, and can also assist in aerial navigation.
[7] A bird sitting on a high tension electric wire does not get electrocuted because –
A.
it has high resistance
B.
the body is earthed
C.
it does not form a closed path for the flow of current
D.
its feet are good insulators
Ans:
it does not form a closed path for the flow of current
Explanation :
Electricity travels from a place of high voltage to low voltage, just as water travels from high elevation to low elevation. A bird, or any living thing, that touches a wire (where electricity is moving from high voltage to low voltage) and also touches the ground (a place with no voltage) creates a path that allows the electricity to travel through that body and into the place with no voltage. When electricity travels through a body in this fashion, electrocution takes place, and the bird can die.
[8] A vacuum cleaner works on the principle of pressure difference. On the moon it will –
A.
work as efficiently as on the earth
B.
not work at all
C.
work with reduced efficiency
D.
work with increased efficiency
Ans:
not work at all
Explanation :
Vacuum cleaners work by creating a lower pressure just inside the opening which touches the floor. By creating a low pressure inside the machine, higher air pressure in the room pushes its way into the vacuum cleaner, taking the dirt with it.
[9] The propagation of sound waves in a gas involves –
A.
Adiabatic compression and rarefaction
B.
Isothermal compression and rarefaction
C.
Isochoric compression and rarefaction
D.
Isobaric compression and rarefaction
Ans:
Adiabatic compression and rarefaction
Explanation :
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing. During propagation, waves can be reflected, refracted, or attenuated by the medium. Sound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves.
[10] When a body is taken from earth to moon –
A.
Mass changes but weight remains same
B.
Weight changes but mass remains same
C.
Both weight and mass change
D.
Both weight and mass re-main same
Ans:
Weight changes but mass remains same
Explanation :
Mass is how much stuff we are made of, and it is the same whether we are on Earth, on the moon, on Mercury, or anywhere else one can think of. We are held on Earth by gravity. Gravity pulling on mass is our weight .
[11] Superconductors are those elements –
A.
Whose conductivity is intermediate between metals and insulators
B.
Whose resistance falls almost to zero at very low temperature
C.
Which conduct electricity only at super-high temperature
D.
Which conduct electricity only, at super-high temperatures
Ans:
Whose resistance falls almost to zero at very low temperature
Explanation :
Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state.
[12] Ail oil drop spreads over water because –
A.
oil is lighter than water
B.
oil is more viscous
C.
oil does not mix with water
D.
surface tension of oil is much smaller than that of water
Ans:
surface tension of oil is much smaller than that of water
Explanation :
Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in the floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects (e.g. water striders) to run on the water surface. This property is caused by cohesion of similar molecules, and is responsible for many of the behaviors of liquids.
[13] The nature of fuse wire is –
A.
high resistance and low melting point.
B.
high resistance and high melting point.
C.
low resistance and high melting point.
D.
low resistance and low melting point.
Ans:
high resistance and low melting point.
Explanation :
A fuse or fusable link works by opening an electrical circuit when the current becomes too high. As the current increases, the temperature of the wire increases. So a fuse wire should have a low melting point and should be connected in series with the appliance. Besides, it should have a comparatively high resistance.
[14] In a railway track, two rails are joined end to end with a gap in between them because –
A.
steel can be saved
B.
accidents due to contraction in winter can be avoided
C.
air-gaps are necessary for bearing the weight of running train
D.
accidents due to expansion in summer can be avoided.
Ans:
accidents due to expansion in summer can be avoided.
Explanation :
The volume of materials changes depending on current temperature. Usually heat makes them expand, and cold leads them to contract. There have to be gaps to avoid strain on the tracks. The same applies in many other fields of engineering, i.e. bridge building.
[15] When a pall of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is –
A.
below a certain minimum value irrespective of amour of water In the pail
B.
above a certain minimum value irrespective of amount of water in the pail
C.
above a certain minimum value depending on amount of water in the pail
D.
below a certain minimum value depending on amount of water in the pail
Ans:
above a certain minimum value irrespective of amount of water in the pail
Explanation :
When a pail of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is great enough. At every point in the circle the water tries to fall vertically out due to the force of gravity g but also tries to move in a straight line due to its circular motion.
[16] Vehicle tyres are inflated properly –
A.
to ensure smooth running.
B.
to allow the vehicle to take more load.
C.
to avoid skidding and to minimize friction
D.
to go fast and save fuel.
Ans:
to avoid skidding and to minimize friction
Explanation :
Under-inflated tyres create more friction with the road, increasing fuel consumption by up to ten per cent and are prone to skidding on either wet or slippery surfaces. Low pressures also lead to premature wear and risk of tyre blowout or bulging.
[17] Refrigeration is a process which –
A.
kills bacteria
B.
slows down the bacterial growth
C.
Inactivates the bacteria
D.
Plasmolyses the bacteria
Ans:
slows down the bacterial growth
Explanation :
Bacteria thrive in warm, moist conditions. Refrigeration allows the temperature to be lowered so far that food can be stored for days or even months. Keeping food cold (at or below 4°C) slows down bacterial growth which helps reduce the risk of food borne illness.
[18] The function of ball bearings in a wheel is –
A.
to increase friction
B.
to convert kinetic friction into rolling friction
C.
to convert static friction into kinetic friction
D.
just for convenience
Ans:
to convert kinetic friction into rolling friction
Explanation :
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
[19] Which of the following is not a property of heavy water?
A.
Boiling point of heavy water is lower than that or ordinary water
B.
Density of heavy water is higher than that of ordinary water
C.
Freezing point of heavy water is higher than that of ordinary water
D.
It produces corrosion
Ans:
Boiling point of heavy water is lower than that or ordinary water
Explanation :
Heavy water, formally called deuterium oxide or 2H2O or D2O, is a form of water that contains the hydrogen isotope deuterium, rather than the common protium isotope. The colloquial term heavy water is often also used to refer a highly enriched water mixture that contains mostly deuterium oxide but also contains some ordinary water molecules as well: for instance heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction. In comparison, in ordinary water, there are only about 156 deuterium atoms per million hydrogen atoms). In its pure form, it has a density about 11% greater than water, but otherwise, is physically and chemically similar. Heavy water is 10.6% denser than ordinary water, a difference which is not immediately obvious.
[20] A mirage occurs because of –
A.
Reflection by hot ground
B.
Total internal reflection by layers of air
C.
Interference of light
D.
Diffraction of light
Ans:
Total internal reflection by layers of air
Explanation :
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and "Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically-stacked images, which form one rapidly-changing mirage. Cold air is denser than warm air and has therefore a greater refractive index.
[21] Knot is a measure of –
A.
The speed of ship
B.
The curvature of spherical objects
C.
Solar radiation
D.
Intensity of earthquake shock
Ans:
The speed of ship
Explanation :
The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. There is no standard abbreviation but km is commonly used. The knot is a non-SI unit accepted for use with the International System of Units (SI).
[22] When the main switch of the house is put off it disconnects the –
A.
live wire only
B.
live wire and the earth wire
C.
live wire and the neutral wire
D.
earth wire and the neutral wire
Ans:
live wire and the neutral wire
Explanation :
Three wires enter most homes from the power pole—two "hot" wires and a third "neutral" wire. Each hot wire provides 120-volt current for conventional lights, receptacles, and appliances when paired with the neutral wire, which is normally kept at zero volts or "ground potential." When both, hot wires are used together with the neutral, they power large 240-volt appliances such as air conditioners and electric ovens. All the electric appliances stop working in a house when the main switch is put off because the electric circuit (the path where the electricity travels) gets opened.
[23] Negative feedback in amplifiers –
A.
increases bandwidth and decreases noise
B.
decreases bandwidth and decreases noise
C.
increases bandwidth and increases noise
D.
decreases bandwidth and increases noise
Ans:
increases bandwidth and decreases noise
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
In automobiles, a bumper is the front-most or rear-most part., ostensibly designed to allow the car to sustain an impact without damage to the vehicle's safety systems. They are not capable of reducing injury to vehicle occupants in high-speed impacts, but are increasingly being designed to mitigate injury to pedestrians struck by cars.
[6] Light houses are places with powerful lights to :
A.
guide and resolve traffic jams in crowded metrocities during nights.
B.
guide and help large crowds at religious gathering during nights.
C.
indicate to the incoming warships, the location of a harbour during night.
D.
guide and warn the ships coming from different directions in the ocean.
Ans:
guide and warn the ships coming from different directions in the ocean.
Explanation :
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses and used as an aid to navigation for maritime pilots at sea or on inland waterways. Lighthouses mark dangerous coastlines, hazardous shoals, reefs, safe entries to harbors, and can also assist in aerial navigation.
[7] A bird sitting on a high tension electric wire does not get electrocuted because –
A.
it has high resistance
B.
the body is earthed
C.
it does not form a closed path for the flow of current
D.
its feet are good insulators
Ans:
it does not form a closed path for the flow of current
Explanation :
Electricity travels from a place of high voltage to low voltage, just as water travels from high elevation to low elevation. A bird, or any living thing, that touches a wire (where electricity is moving from high voltage to low voltage) and also touches the ground (a place with no voltage) creates a path that allows the electricity to travel through that body and into the place with no voltage. When electricity travels through a body in this fashion, electrocution takes place, and the bird can die.
[8] A vacuum cleaner works on the principle of pressure difference. On the moon it will –
A.
work as efficiently as on the earth
B.
not work at all
C.
work with reduced efficiency
D.
work with increased efficiency
Ans:
not work at all
Explanation :
Vacuum cleaners work by creating a lower pressure just inside the opening which touches the floor. By creating a low pressure inside the machine, higher air pressure in the room pushes its way into the vacuum cleaner, taking the dirt with it.
[9] The propagation of sound waves in a gas involves –
A.
Adiabatic compression and rarefaction
B.
Isothermal compression and rarefaction
C.
Isochoric compression and rarefaction
D.
Isobaric compression and rarefaction
Ans:
Adiabatic compression and rarefaction
Explanation :
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing. During propagation, waves can be reflected, refracted, or attenuated by the medium. Sound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves.
[10] When a body is taken from earth to moon –
A.
Mass changes but weight remains same
B.
Weight changes but mass remains same
C.
Both weight and mass change
D.
Both weight and mass re-main same
Ans:
Weight changes but mass remains same
Explanation :
Mass is how much stuff we are made of, and it is the same whether we are on Earth, on the moon, on Mercury, or anywhere else one can think of. We are held on Earth by gravity. Gravity pulling on mass is our weight .
[11] Superconductors are those elements –
A.
Whose conductivity is intermediate between metals and insulators
B.
Whose resistance falls almost to zero at very low temperature
C.
Which conduct electricity only at super-high temperature
D.
Which conduct electricity only, at super-high temperatures
Ans:
Whose resistance falls almost to zero at very low temperature
Explanation :
Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state.
[12] Ail oil drop spreads over water because –
A.
oil is lighter than water
B.
oil is more viscous
C.
oil does not mix with water
D.
surface tension of oil is much smaller than that of water
Ans:
surface tension of oil is much smaller than that of water
Explanation :
Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in the floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects (e.g. water striders) to run on the water surface. This property is caused by cohesion of similar molecules, and is responsible for many of the behaviors of liquids.
[13] The nature of fuse wire is –
A.
high resistance and low melting point.
B.
high resistance and high melting point.
C.
low resistance and high melting point.
D.
low resistance and low melting point.
Ans:
high resistance and low melting point.
Explanation :
A fuse or fusable link works by opening an electrical circuit when the current becomes too high. As the current increases, the temperature of the wire increases. So a fuse wire should have a low melting point and should be connected in series with the appliance. Besides, it should have a comparatively high resistance.
[14] In a railway track, two rails are joined end to end with a gap in between them because –
A.
steel can be saved
B.
accidents due to contraction in winter can be avoided
C.
air-gaps are necessary for bearing the weight of running train
D.
accidents due to expansion in summer can be avoided.
Ans:
accidents due to expansion in summer can be avoided.
Explanation :
The volume of materials changes depending on current temperature. Usually heat makes them expand, and cold leads them to contract. There have to be gaps to avoid strain on the tracks. The same applies in many other fields of engineering, i.e. bridge building.
[15] When a pall of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is –
A.
below a certain minimum value irrespective of amour of water In the pail
B.
above a certain minimum value irrespective of amount of water in the pail
C.
above a certain minimum value depending on amount of water in the pail
D.
below a certain minimum value depending on amount of water in the pail
Ans:
above a certain minimum value irrespective of amount of water in the pail
Explanation :
When a pail of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is great enough. At every point in the circle the water tries to fall vertically out due to the force of gravity g but also tries to move in a straight line due to its circular motion.
[16] Vehicle tyres are inflated properly –
A.
to ensure smooth running.
B.
to allow the vehicle to take more load.
C.
to avoid skidding and to minimize friction
D.
to go fast and save fuel.
Ans:
to avoid skidding and to minimize friction
Explanation :
Under-inflated tyres create more friction with the road, increasing fuel consumption by up to ten per cent and are prone to skidding on either wet or slippery surfaces. Low pressures also lead to premature wear and risk of tyre blowout or bulging.
[17] Refrigeration is a process which –
A.
kills bacteria
B.
slows down the bacterial growth
C.
Inactivates the bacteria
D.
Plasmolyses the bacteria
Ans:
slows down the bacterial growth
Explanation :
Bacteria thrive in warm, moist conditions. Refrigeration allows the temperature to be lowered so far that food can be stored for days or even months. Keeping food cold (at or below 4°C) slows down bacterial growth which helps reduce the risk of food borne illness.
[18] The function of ball bearings in a wheel is –
A.
to increase friction
B.
to convert kinetic friction into rolling friction
C.
to convert static friction into kinetic friction
D.
just for convenience
Ans:
to convert kinetic friction into rolling friction
Explanation :
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
[19] Which of the following is not a property of heavy water?
A.
Boiling point of heavy water is lower than that or ordinary water
B.
Density of heavy water is higher than that of ordinary water
C.
Freezing point of heavy water is higher than that of ordinary water
D.
It produces corrosion
Ans:
Boiling point of heavy water is lower than that or ordinary water
Explanation :
Heavy water, formally called deuterium oxide or 2H2O or D2O, is a form of water that contains the hydrogen isotope deuterium, rather than the common protium isotope. The colloquial term heavy water is often also used to refer a highly enriched water mixture that contains mostly deuterium oxide but also contains some ordinary water molecules as well: for instance heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction. In comparison, in ordinary water, there are only about 156 deuterium atoms per million hydrogen atoms). In its pure form, it has a density about 11% greater than water, but otherwise, is physically and chemically similar. Heavy water is 10.6% denser than ordinary water, a difference which is not immediately obvious.
[20] A mirage occurs because of –
A.
Reflection by hot ground
B.
Total internal reflection by layers of air
C.
Interference of light
D.
Diffraction of light
Ans:
Total internal reflection by layers of air
Explanation :
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and "Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically-stacked images, which form one rapidly-changing mirage. Cold air is denser than warm air and has therefore a greater refractive index.
[21] Knot is a measure of –
A.
The speed of ship
B.
The curvature of spherical objects
C.
Solar radiation
D.
Intensity of earthquake shock
Ans:
The speed of ship
Explanation :
The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. There is no standard abbreviation but km is commonly used. The knot is a non-SI unit accepted for use with the International System of Units (SI).
[22] When the main switch of the house is put off it disconnects the –
A.
live wire only
B.
live wire and the earth wire
C.
live wire and the neutral wire
D.
earth wire and the neutral wire
Ans:
live wire and the neutral wire
Explanation :
Three wires enter most homes from the power pole—two "hot" wires and a third "neutral" wire. Each hot wire provides 120-volt current for conventional lights, receptacles, and appliances when paired with the neutral wire, which is normally kept at zero volts or "ground potential." When both, hot wires are used together with the neutral, they power large 240-volt appliances such as air conditioners and electric ovens. All the electric appliances stop working in a house when the main switch is put off because the electric circuit (the path where the electricity travels) gets opened.
[23] Negative feedback in amplifiers –
A.
increases bandwidth and decreases noise
B.
decreases bandwidth and decreases noise
C.
increases bandwidth and increases noise
D.
decreases bandwidth and increases noise
Ans:
increases bandwidth and decreases noise
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
Electricity travels from a place of high voltage to low voltage, just as water travels from high elevation to low elevation. A bird, or any living thing, that touches a wire (where electricity is moving from high voltage to low voltage) and also touches the ground (a place with no voltage) creates a path that allows the electricity to travel through that body and into the place with no voltage. When electricity travels through a body in this fashion, electrocution takes place, and the bird can die.
[8] A vacuum cleaner works on the principle of pressure difference. On the moon it will –
A.
work as efficiently as on the earth
B.
not work at all
C.
work with reduced efficiency
D.
work with increased efficiency
Ans:
not work at all
Explanation :
Vacuum cleaners work by creating a lower pressure just inside the opening which touches the floor. By creating a low pressure inside the machine, higher air pressure in the room pushes its way into the vacuum cleaner, taking the dirt with it.
[9] The propagation of sound waves in a gas involves –
A.
Adiabatic compression and rarefaction
B.
Isothermal compression and rarefaction
C.
Isochoric compression and rarefaction
D.
Isobaric compression and rarefaction
Ans:
Adiabatic compression and rarefaction
Explanation :
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing. During propagation, waves can be reflected, refracted, or attenuated by the medium. Sound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves.
[10] When a body is taken from earth to moon –
A.
Mass changes but weight remains same
B.
Weight changes but mass remains same
C.
Both weight and mass change
D.
Both weight and mass re-main same
Ans:
Weight changes but mass remains same
Explanation :
Mass is how much stuff we are made of, and it is the same whether we are on Earth, on the moon, on Mercury, or anywhere else one can think of. We are held on Earth by gravity. Gravity pulling on mass is our weight .
[11] Superconductors are those elements –
A.
Whose conductivity is intermediate between metals and insulators
B.
Whose resistance falls almost to zero at very low temperature
C.
Which conduct electricity only at super-high temperature
D.
Which conduct electricity only, at super-high temperatures
Ans:
Whose resistance falls almost to zero at very low temperature
Explanation :
Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state.
[12] Ail oil drop spreads over water because –
A.
oil is lighter than water
B.
oil is more viscous
C.
oil does not mix with water
D.
surface tension of oil is much smaller than that of water
Ans:
surface tension of oil is much smaller than that of water
Explanation :
Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in the floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects (e.g. water striders) to run on the water surface. This property is caused by cohesion of similar molecules, and is responsible for many of the behaviors of liquids.
[13] The nature of fuse wire is –
A.
high resistance and low melting point.
B.
high resistance and high melting point.
C.
low resistance and high melting point.
D.
low resistance and low melting point.
Ans:
high resistance and low melting point.
Explanation :
A fuse or fusable link works by opening an electrical circuit when the current becomes too high. As the current increases, the temperature of the wire increases. So a fuse wire should have a low melting point and should be connected in series with the appliance. Besides, it should have a comparatively high resistance.
[14] In a railway track, two rails are joined end to end with a gap in between them because –
A.
steel can be saved
B.
accidents due to contraction in winter can be avoided
C.
air-gaps are necessary for bearing the weight of running train
D.
accidents due to expansion in summer can be avoided.
Ans:
accidents due to expansion in summer can be avoided.
Explanation :
The volume of materials changes depending on current temperature. Usually heat makes them expand, and cold leads them to contract. There have to be gaps to avoid strain on the tracks. The same applies in many other fields of engineering, i.e. bridge building.
[15] When a pall of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is –
A.
below a certain minimum value irrespective of amour of water In the pail
B.
above a certain minimum value irrespective of amount of water in the pail
C.
above a certain minimum value depending on amount of water in the pail
D.
below a certain minimum value depending on amount of water in the pail
Ans:
above a certain minimum value irrespective of amount of water in the pail
Explanation :
When a pail of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is great enough. At every point in the circle the water tries to fall vertically out due to the force of gravity g but also tries to move in a straight line due to its circular motion.
[16] Vehicle tyres are inflated properly –
A.
to ensure smooth running.
B.
to allow the vehicle to take more load.
C.
to avoid skidding and to minimize friction
D.
to go fast and save fuel.
Ans:
to avoid skidding and to minimize friction
Explanation :
Under-inflated tyres create more friction with the road, increasing fuel consumption by up to ten per cent and are prone to skidding on either wet or slippery surfaces. Low pressures also lead to premature wear and risk of tyre blowout or bulging.
[17] Refrigeration is a process which –
A.
kills bacteria
B.
slows down the bacterial growth
C.
Inactivates the bacteria
D.
Plasmolyses the bacteria
Ans:
slows down the bacterial growth
Explanation :
Bacteria thrive in warm, moist conditions. Refrigeration allows the temperature to be lowered so far that food can be stored for days or even months. Keeping food cold (at or below 4°C) slows down bacterial growth which helps reduce the risk of food borne illness.
[18] The function of ball bearings in a wheel is –
A.
to increase friction
B.
to convert kinetic friction into rolling friction
C.
to convert static friction into kinetic friction
D.
just for convenience
Ans:
to convert kinetic friction into rolling friction
Explanation :
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
[19] Which of the following is not a property of heavy water?
A.
Boiling point of heavy water is lower than that or ordinary water
B.
Density of heavy water is higher than that of ordinary water
C.
Freezing point of heavy water is higher than that of ordinary water
D.
It produces corrosion
Ans:
Boiling point of heavy water is lower than that or ordinary water
Explanation :
Heavy water, formally called deuterium oxide or 2H2O or D2O, is a form of water that contains the hydrogen isotope deuterium, rather than the common protium isotope. The colloquial term heavy water is often also used to refer a highly enriched water mixture that contains mostly deuterium oxide but also contains some ordinary water molecules as well: for instance heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction. In comparison, in ordinary water, there are only about 156 deuterium atoms per million hydrogen atoms). In its pure form, it has a density about 11% greater than water, but otherwise, is physically and chemically similar. Heavy water is 10.6% denser than ordinary water, a difference which is not immediately obvious.
[20] A mirage occurs because of –
A.
Reflection by hot ground
B.
Total internal reflection by layers of air
C.
Interference of light
D.
Diffraction of light
Ans:
Total internal reflection by layers of air
Explanation :
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and "Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically-stacked images, which form one rapidly-changing mirage. Cold air is denser than warm air and has therefore a greater refractive index.
[21] Knot is a measure of –
A.
The speed of ship
B.
The curvature of spherical objects
C.
Solar radiation
D.
Intensity of earthquake shock
Ans:
The speed of ship
Explanation :
The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. There is no standard abbreviation but km is commonly used. The knot is a non-SI unit accepted for use with the International System of Units (SI).
[22] When the main switch of the house is put off it disconnects the –
A.
live wire only
B.
live wire and the earth wire
C.
live wire and the neutral wire
D.
earth wire and the neutral wire
Ans:
live wire and the neutral wire
Explanation :
Three wires enter most homes from the power pole—two "hot" wires and a third "neutral" wire. Each hot wire provides 120-volt current for conventional lights, receptacles, and appliances when paired with the neutral wire, which is normally kept at zero volts or "ground potential." When both, hot wires are used together with the neutral, they power large 240-volt appliances such as air conditioners and electric ovens. All the electric appliances stop working in a house when the main switch is put off because the electric circuit (the path where the electricity travels) gets opened.
[23] Negative feedback in amplifiers –
A.
increases bandwidth and decreases noise
B.
decreases bandwidth and decreases noise
C.
increases bandwidth and increases noise
D.
decreases bandwidth and increases noise
Ans:
increases bandwidth and decreases noise
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing. During propagation, waves can be reflected, refracted, or attenuated by the medium. Sound is transmitted through gases, plasma, and liquids as longitudinal waves, also called compression waves.
[10] When a body is taken from earth to moon –
A.
Mass changes but weight remains same
B.
Weight changes but mass remains same
C.
Both weight and mass change
D.
Both weight and mass re-main same
Ans:
Weight changes but mass remains same
Explanation :
Mass is how much stuff we are made of, and it is the same whether we are on Earth, on the moon, on Mercury, or anywhere else one can think of. We are held on Earth by gravity. Gravity pulling on mass is our weight .
[11] Superconductors are those elements –
A.
Whose conductivity is intermediate between metals and insulators
B.
Whose resistance falls almost to zero at very low temperature
C.
Which conduct electricity only at super-high temperature
D.
Which conduct electricity only, at super-high temperatures
Ans:
Whose resistance falls almost to zero at very low temperature
Explanation :
Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state.
[12] Ail oil drop spreads over water because –
A.
oil is lighter than water
B.
oil is more viscous
C.
oil does not mix with water
D.
surface tension of oil is much smaller than that of water
Ans:
surface tension of oil is much smaller than that of water
Explanation :
Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in the floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects (e.g. water striders) to run on the water surface. This property is caused by cohesion of similar molecules, and is responsible for many of the behaviors of liquids.
[13] The nature of fuse wire is –
A.
high resistance and low melting point.
B.
high resistance and high melting point.
C.
low resistance and high melting point.
D.
low resistance and low melting point.
Ans:
high resistance and low melting point.
Explanation :
A fuse or fusable link works by opening an electrical circuit when the current becomes too high. As the current increases, the temperature of the wire increases. So a fuse wire should have a low melting point and should be connected in series with the appliance. Besides, it should have a comparatively high resistance.
[14] In a railway track, two rails are joined end to end with a gap in between them because –
A.
steel can be saved
B.
accidents due to contraction in winter can be avoided
C.
air-gaps are necessary for bearing the weight of running train
D.
accidents due to expansion in summer can be avoided.
Ans:
accidents due to expansion in summer can be avoided.
Explanation :
The volume of materials changes depending on current temperature. Usually heat makes them expand, and cold leads them to contract. There have to be gaps to avoid strain on the tracks. The same applies in many other fields of engineering, i.e. bridge building.
[15] When a pall of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is –
A.
below a certain minimum value irrespective of amour of water In the pail
B.
above a certain minimum value irrespective of amount of water in the pail
C.
above a certain minimum value depending on amount of water in the pail
D.
below a certain minimum value depending on amount of water in the pail
Ans:
above a certain minimum value irrespective of amount of water in the pail
Explanation :
When a pail of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is great enough. At every point in the circle the water tries to fall vertically out due to the force of gravity g but also tries to move in a straight line due to its circular motion.
[16] Vehicle tyres are inflated properly –
A.
to ensure smooth running.
B.
to allow the vehicle to take more load.
C.
to avoid skidding and to minimize friction
D.
to go fast and save fuel.
Ans:
to avoid skidding and to minimize friction
Explanation :
Under-inflated tyres create more friction with the road, increasing fuel consumption by up to ten per cent and are prone to skidding on either wet or slippery surfaces. Low pressures also lead to premature wear and risk of tyre blowout or bulging.
[17] Refrigeration is a process which –
A.
kills bacteria
B.
slows down the bacterial growth
C.
Inactivates the bacteria
D.
Plasmolyses the bacteria
Ans:
slows down the bacterial growth
Explanation :
Bacteria thrive in warm, moist conditions. Refrigeration allows the temperature to be lowered so far that food can be stored for days or even months. Keeping food cold (at or below 4°C) slows down bacterial growth which helps reduce the risk of food borne illness.
[18] The function of ball bearings in a wheel is –
A.
to increase friction
B.
to convert kinetic friction into rolling friction
C.
to convert static friction into kinetic friction
D.
just for convenience
Ans:
to convert kinetic friction into rolling friction
Explanation :
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
[19] Which of the following is not a property of heavy water?
A.
Boiling point of heavy water is lower than that or ordinary water
B.
Density of heavy water is higher than that of ordinary water
C.
Freezing point of heavy water is higher than that of ordinary water
D.
It produces corrosion
Ans:
Boiling point of heavy water is lower than that or ordinary water
Explanation :
Heavy water, formally called deuterium oxide or 2H2O or D2O, is a form of water that contains the hydrogen isotope deuterium, rather than the common protium isotope. The colloquial term heavy water is often also used to refer a highly enriched water mixture that contains mostly deuterium oxide but also contains some ordinary water molecules as well: for instance heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction. In comparison, in ordinary water, there are only about 156 deuterium atoms per million hydrogen atoms). In its pure form, it has a density about 11% greater than water, but otherwise, is physically and chemically similar. Heavy water is 10.6% denser than ordinary water, a difference which is not immediately obvious.
[20] A mirage occurs because of –
A.
Reflection by hot ground
B.
Total internal reflection by layers of air
C.
Interference of light
D.
Diffraction of light
Ans:
Total internal reflection by layers of air
Explanation :
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and "Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically-stacked images, which form one rapidly-changing mirage. Cold air is denser than warm air and has therefore a greater refractive index.
[21] Knot is a measure of –
A.
The speed of ship
B.
The curvature of spherical objects
C.
Solar radiation
D.
Intensity of earthquake shock
Ans:
The speed of ship
Explanation :
The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. There is no standard abbreviation but km is commonly used. The knot is a non-SI unit accepted for use with the International System of Units (SI).
[22] When the main switch of the house is put off it disconnects the –
A.
live wire only
B.
live wire and the earth wire
C.
live wire and the neutral wire
D.
earth wire and the neutral wire
Ans:
live wire and the neutral wire
Explanation :
Three wires enter most homes from the power pole—two "hot" wires and a third "neutral" wire. Each hot wire provides 120-volt current for conventional lights, receptacles, and appliances when paired with the neutral wire, which is normally kept at zero volts or "ground potential." When both, hot wires are used together with the neutral, they power large 240-volt appliances such as air conditioners and electric ovens. All the electric appliances stop working in a house when the main switch is put off because the electric circuit (the path where the electricity travels) gets opened.
[23] Negative feedback in amplifiers –
A.
increases bandwidth and decreases noise
B.
decreases bandwidth and decreases noise
C.
increases bandwidth and increases noise
D.
decreases bandwidth and increases noise
Ans:
increases bandwidth and decreases noise
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor as it transitions into the superconducting state.
[12] Ail oil drop spreads over water because –
A.
oil is lighter than water
B.
oil is more viscous
C.
oil does not mix with water
D.
surface tension of oil is much smaller than that of water
Ans:
surface tension of oil is much smaller than that of water
Explanation :
Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force. It is revealed, for example, in the floating of some objects on the surface of water, even though they are denser than water, and in the ability of some insects (e.g. water striders) to run on the water surface. This property is caused by cohesion of similar molecules, and is responsible for many of the behaviors of liquids.
[13] The nature of fuse wire is –
A.
high resistance and low melting point.
B.
high resistance and high melting point.
C.
low resistance and high melting point.
D.
low resistance and low melting point.
Ans:
high resistance and low melting point.
Explanation :
A fuse or fusable link works by opening an electrical circuit when the current becomes too high. As the current increases, the temperature of the wire increases. So a fuse wire should have a low melting point and should be connected in series with the appliance. Besides, it should have a comparatively high resistance.
[14] In a railway track, two rails are joined end to end with a gap in between them because –
A.
steel can be saved
B.
accidents due to contraction in winter can be avoided
C.
air-gaps are necessary for bearing the weight of running train
D.
accidents due to expansion in summer can be avoided.
Ans:
accidents due to expansion in summer can be avoided.
Explanation :
The volume of materials changes depending on current temperature. Usually heat makes them expand, and cold leads them to contract. There have to be gaps to avoid strain on the tracks. The same applies in many other fields of engineering, i.e. bridge building.
[15] When a pall of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is –
A.
below a certain minimum value irrespective of amour of water In the pail
B.
above a certain minimum value irrespective of amount of water in the pail
C.
above a certain minimum value depending on amount of water in the pail
D.
below a certain minimum value depending on amount of water in the pail
Ans:
above a certain minimum value irrespective of amount of water in the pail
Explanation :
When a pail of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is great enough. At every point in the circle the water tries to fall vertically out due to the force of gravity g but also tries to move in a straight line due to its circular motion.
[16] Vehicle tyres are inflated properly –
A.
to ensure smooth running.
B.
to allow the vehicle to take more load.
C.
to avoid skidding and to minimize friction
D.
to go fast and save fuel.
Ans:
to avoid skidding and to minimize friction
Explanation :
Under-inflated tyres create more friction with the road, increasing fuel consumption by up to ten per cent and are prone to skidding on either wet or slippery surfaces. Low pressures also lead to premature wear and risk of tyre blowout or bulging.
[17] Refrigeration is a process which –
A.
kills bacteria
B.
slows down the bacterial growth
C.
Inactivates the bacteria
D.
Plasmolyses the bacteria
Ans:
slows down the bacterial growth
Explanation :
Bacteria thrive in warm, moist conditions. Refrigeration allows the temperature to be lowered so far that food can be stored for days or even months. Keeping food cold (at or below 4°C) slows down bacterial growth which helps reduce the risk of food borne illness.
[18] The function of ball bearings in a wheel is –
A.
to increase friction
B.
to convert kinetic friction into rolling friction
C.
to convert static friction into kinetic friction
D.
just for convenience
Ans:
to convert kinetic friction into rolling friction
Explanation :
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
[19] Which of the following is not a property of heavy water?
A.
Boiling point of heavy water is lower than that or ordinary water
B.
Density of heavy water is higher than that of ordinary water
C.
Freezing point of heavy water is higher than that of ordinary water
D.
It produces corrosion
Ans:
Boiling point of heavy water is lower than that or ordinary water
Explanation :
Heavy water, formally called deuterium oxide or 2H2O or D2O, is a form of water that contains the hydrogen isotope deuterium, rather than the common protium isotope. The colloquial term heavy water is often also used to refer a highly enriched water mixture that contains mostly deuterium oxide but also contains some ordinary water molecules as well: for instance heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction. In comparison, in ordinary water, there are only about 156 deuterium atoms per million hydrogen atoms). In its pure form, it has a density about 11% greater than water, but otherwise, is physically and chemically similar. Heavy water is 10.6% denser than ordinary water, a difference which is not immediately obvious.
[20] A mirage occurs because of –
A.
Reflection by hot ground
B.
Total internal reflection by layers of air
C.
Interference of light
D.
Diffraction of light
Ans:
Total internal reflection by layers of air
Explanation :
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and "Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically-stacked images, which form one rapidly-changing mirage. Cold air is denser than warm air and has therefore a greater refractive index.
[21] Knot is a measure of –
A.
The speed of ship
B.
The curvature of spherical objects
C.
Solar radiation
D.
Intensity of earthquake shock
Ans:
The speed of ship
Explanation :
The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. There is no standard abbreviation but km is commonly used. The knot is a non-SI unit accepted for use with the International System of Units (SI).
[22] When the main switch of the house is put off it disconnects the –
A.
live wire only
B.
live wire and the earth wire
C.
live wire and the neutral wire
D.
earth wire and the neutral wire
Ans:
live wire and the neutral wire
Explanation :
Three wires enter most homes from the power pole—two "hot" wires and a third "neutral" wire. Each hot wire provides 120-volt current for conventional lights, receptacles, and appliances when paired with the neutral wire, which is normally kept at zero volts or "ground potential." When both, hot wires are used together with the neutral, they power large 240-volt appliances such as air conditioners and electric ovens. All the electric appliances stop working in a house when the main switch is put off because the electric circuit (the path where the electricity travels) gets opened.
[23] Negative feedback in amplifiers –
A.
increases bandwidth and decreases noise
B.
decreases bandwidth and decreases noise
C.
increases bandwidth and increases noise
D.
decreases bandwidth and increases noise
Ans:
increases bandwidth and decreases noise
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
A fuse or fusable link works by opening an electrical circuit when the current becomes too high. As the current increases, the temperature of the wire increases. So a fuse wire should have a low melting point and should be connected in series with the appliance. Besides, it should have a comparatively high resistance.
[14] In a railway track, two rails are joined end to end with a gap in between them because –
A.
steel can be saved
B.
accidents due to contraction in winter can be avoided
C.
air-gaps are necessary for bearing the weight of running train
D.
accidents due to expansion in summer can be avoided.
Ans:
accidents due to expansion in summer can be avoided.
Explanation :
The volume of materials changes depending on current temperature. Usually heat makes them expand, and cold leads them to contract. There have to be gaps to avoid strain on the tracks. The same applies in many other fields of engineering, i.e. bridge building.
[15] When a pall of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is –
A.
below a certain minimum value irrespective of amour of water In the pail
B.
above a certain minimum value irrespective of amount of water in the pail
C.
above a certain minimum value depending on amount of water in the pail
D.
below a certain minimum value depending on amount of water in the pail
Ans:
above a certain minimum value irrespective of amount of water in the pail
Explanation :
When a pail of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is great enough. At every point in the circle the water tries to fall vertically out due to the force of gravity g but also tries to move in a straight line due to its circular motion.
[16] Vehicle tyres are inflated properly –
A.
to ensure smooth running.
B.
to allow the vehicle to take more load.
C.
to avoid skidding and to minimize friction
D.
to go fast and save fuel.
Ans:
to avoid skidding and to minimize friction
Explanation :
Under-inflated tyres create more friction with the road, increasing fuel consumption by up to ten per cent and are prone to skidding on either wet or slippery surfaces. Low pressures also lead to premature wear and risk of tyre blowout or bulging.
[17] Refrigeration is a process which –
A.
kills bacteria
B.
slows down the bacterial growth
C.
Inactivates the bacteria
D.
Plasmolyses the bacteria
Ans:
slows down the bacterial growth
Explanation :
Bacteria thrive in warm, moist conditions. Refrigeration allows the temperature to be lowered so far that food can be stored for days or even months. Keeping food cold (at or below 4°C) slows down bacterial growth which helps reduce the risk of food borne illness.
[18] The function of ball bearings in a wheel is –
A.
to increase friction
B.
to convert kinetic friction into rolling friction
C.
to convert static friction into kinetic friction
D.
just for convenience
Ans:
to convert kinetic friction into rolling friction
Explanation :
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
[19] Which of the following is not a property of heavy water?
A.
Boiling point of heavy water is lower than that or ordinary water
B.
Density of heavy water is higher than that of ordinary water
C.
Freezing point of heavy water is higher than that of ordinary water
D.
It produces corrosion
Ans:
Boiling point of heavy water is lower than that or ordinary water
Explanation :
Heavy water, formally called deuterium oxide or 2H2O or D2O, is a form of water that contains the hydrogen isotope deuterium, rather than the common protium isotope. The colloquial term heavy water is often also used to refer a highly enriched water mixture that contains mostly deuterium oxide but also contains some ordinary water molecules as well: for instance heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction. In comparison, in ordinary water, there are only about 156 deuterium atoms per million hydrogen atoms). In its pure form, it has a density about 11% greater than water, but otherwise, is physically and chemically similar. Heavy water is 10.6% denser than ordinary water, a difference which is not immediately obvious.
[20] A mirage occurs because of –
A.
Reflection by hot ground
B.
Total internal reflection by layers of air
C.
Interference of light
D.
Diffraction of light
Ans:
Total internal reflection by layers of air
Explanation :
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and "Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically-stacked images, which form one rapidly-changing mirage. Cold air is denser than warm air and has therefore a greater refractive index.
[21] Knot is a measure of –
A.
The speed of ship
B.
The curvature of spherical objects
C.
Solar radiation
D.
Intensity of earthquake shock
Ans:
The speed of ship
Explanation :
The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. There is no standard abbreviation but km is commonly used. The knot is a non-SI unit accepted for use with the International System of Units (SI).
[22] When the main switch of the house is put off it disconnects the –
A.
live wire only
B.
live wire and the earth wire
C.
live wire and the neutral wire
D.
earth wire and the neutral wire
Ans:
live wire and the neutral wire
Explanation :
Three wires enter most homes from the power pole—two "hot" wires and a third "neutral" wire. Each hot wire provides 120-volt current for conventional lights, receptacles, and appliances when paired with the neutral wire, which is normally kept at zero volts or "ground potential." When both, hot wires are used together with the neutral, they power large 240-volt appliances such as air conditioners and electric ovens. All the electric appliances stop working in a house when the main switch is put off because the electric circuit (the path where the electricity travels) gets opened.
[23] Negative feedback in amplifiers –
A.
increases bandwidth and decreases noise
B.
decreases bandwidth and decreases noise
C.
increases bandwidth and increases noise
D.
decreases bandwidth and increases noise
Ans:
increases bandwidth and decreases noise
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
When a pail of water is swung in a vertical circle, the water does not fall out at the top of the loop when the speed is great enough. At every point in the circle the water tries to fall vertically out due to the force of gravity g but also tries to move in a straight line due to its circular motion.
[16] Vehicle tyres are inflated properly –
A.
to ensure smooth running.
B.
to allow the vehicle to take more load.
C.
to avoid skidding and to minimize friction
D.
to go fast and save fuel.
Ans:
to avoid skidding and to minimize friction
Explanation :
Under-inflated tyres create more friction with the road, increasing fuel consumption by up to ten per cent and are prone to skidding on either wet or slippery surfaces. Low pressures also lead to premature wear and risk of tyre blowout or bulging.
[17] Refrigeration is a process which –
A.
kills bacteria
B.
slows down the bacterial growth
C.
Inactivates the bacteria
D.
Plasmolyses the bacteria
Ans:
slows down the bacterial growth
Explanation :
Bacteria thrive in warm, moist conditions. Refrigeration allows the temperature to be lowered so far that food can be stored for days or even months. Keeping food cold (at or below 4°C) slows down bacterial growth which helps reduce the risk of food borne illness.
[18] The function of ball bearings in a wheel is –
A.
to increase friction
B.
to convert kinetic friction into rolling friction
C.
to convert static friction into kinetic friction
D.
just for convenience
Ans:
to convert kinetic friction into rolling friction
Explanation :
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
[19] Which of the following is not a property of heavy water?
A.
Boiling point of heavy water is lower than that or ordinary water
B.
Density of heavy water is higher than that of ordinary water
C.
Freezing point of heavy water is higher than that of ordinary water
D.
It produces corrosion
Ans:
Boiling point of heavy water is lower than that or ordinary water
Explanation :
Heavy water, formally called deuterium oxide or 2H2O or D2O, is a form of water that contains the hydrogen isotope deuterium, rather than the common protium isotope. The colloquial term heavy water is often also used to refer a highly enriched water mixture that contains mostly deuterium oxide but also contains some ordinary water molecules as well: for instance heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction. In comparison, in ordinary water, there are only about 156 deuterium atoms per million hydrogen atoms). In its pure form, it has a density about 11% greater than water, but otherwise, is physically and chemically similar. Heavy water is 10.6% denser than ordinary water, a difference which is not immediately obvious.
[20] A mirage occurs because of –
A.
Reflection by hot ground
B.
Total internal reflection by layers of air
C.
Interference of light
D.
Diffraction of light
Ans:
Total internal reflection by layers of air
Explanation :
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and "Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically-stacked images, which form one rapidly-changing mirage. Cold air is denser than warm air and has therefore a greater refractive index.
[21] Knot is a measure of –
A.
The speed of ship
B.
The curvature of spherical objects
C.
Solar radiation
D.
Intensity of earthquake shock
Ans:
The speed of ship
Explanation :
The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. There is no standard abbreviation but km is commonly used. The knot is a non-SI unit accepted for use with the International System of Units (SI).
[22] When the main switch of the house is put off it disconnects the –
A.
live wire only
B.
live wire and the earth wire
C.
live wire and the neutral wire
D.
earth wire and the neutral wire
Ans:
live wire and the neutral wire
Explanation :
Three wires enter most homes from the power pole—two "hot" wires and a third "neutral" wire. Each hot wire provides 120-volt current for conventional lights, receptacles, and appliances when paired with the neutral wire, which is normally kept at zero volts or "ground potential." When both, hot wires are used together with the neutral, they power large 240-volt appliances such as air conditioners and electric ovens. All the electric appliances stop working in a house when the main switch is put off because the electric circuit (the path where the electricity travels) gets opened.
[23] Negative feedback in amplifiers –
A.
increases bandwidth and decreases noise
B.
decreases bandwidth and decreases noise
C.
increases bandwidth and increases noise
D.
decreases bandwidth and increases noise
Ans:
increases bandwidth and decreases noise
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
Bacteria thrive in warm, moist conditions. Refrigeration allows the temperature to be lowered so far that food can be stored for days or even months. Keeping food cold (at or below 4°C) slows down bacterial growth which helps reduce the risk of food borne illness.
[18] The function of ball bearings in a wheel is –
A.
to increase friction
B.
to convert kinetic friction into rolling friction
C.
to convert static friction into kinetic friction
D.
just for convenience
Ans:
to convert kinetic friction into rolling friction
Explanation :
A ball bearing is a type of rolling-element bearing that uses balls to maintain the separation between the bearing races. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads.
[19] Which of the following is not a property of heavy water?
A.
Boiling point of heavy water is lower than that or ordinary water
B.
Density of heavy water is higher than that of ordinary water
C.
Freezing point of heavy water is higher than that of ordinary water
D.
It produces corrosion
Ans:
Boiling point of heavy water is lower than that or ordinary water
Explanation :
Heavy water, formally called deuterium oxide or 2H2O or D2O, is a form of water that contains the hydrogen isotope deuterium, rather than the common protium isotope. The colloquial term heavy water is often also used to refer a highly enriched water mixture that contains mostly deuterium oxide but also contains some ordinary water molecules as well: for instance heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction. In comparison, in ordinary water, there are only about 156 deuterium atoms per million hydrogen atoms). In its pure form, it has a density about 11% greater than water, but otherwise, is physically and chemically similar. Heavy water is 10.6% denser than ordinary water, a difference which is not immediately obvious.
[20] A mirage occurs because of –
A.
Reflection by hot ground
B.
Total internal reflection by layers of air
C.
Interference of light
D.
Diffraction of light
Ans:
Total internal reflection by layers of air
Explanation :
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and "Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically-stacked images, which form one rapidly-changing mirage. Cold air is denser than warm air and has therefore a greater refractive index.
[21] Knot is a measure of –
A.
The speed of ship
B.
The curvature of spherical objects
C.
Solar radiation
D.
Intensity of earthquake shock
Ans:
The speed of ship
Explanation :
The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. There is no standard abbreviation but km is commonly used. The knot is a non-SI unit accepted for use with the International System of Units (SI).
[22] When the main switch of the house is put off it disconnects the –
A.
live wire only
B.
live wire and the earth wire
C.
live wire and the neutral wire
D.
earth wire and the neutral wire
Ans:
live wire and the neutral wire
Explanation :
Three wires enter most homes from the power pole—two "hot" wires and a third "neutral" wire. Each hot wire provides 120-volt current for conventional lights, receptacles, and appliances when paired with the neutral wire, which is normally kept at zero volts or "ground potential." When both, hot wires are used together with the neutral, they power large 240-volt appliances such as air conditioners and electric ovens. All the electric appliances stop working in a house when the main switch is put off because the electric circuit (the path where the electricity travels) gets opened.
[23] Negative feedback in amplifiers –
A.
increases bandwidth and decreases noise
B.
decreases bandwidth and decreases noise
C.
increases bandwidth and increases noise
D.
decreases bandwidth and increases noise
Ans:
increases bandwidth and decreases noise
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
Heavy water, formally called deuterium oxide or 2H2O or D2O, is a form of water that contains the hydrogen isotope deuterium, rather than the common protium isotope. The colloquial term heavy water is often also used to refer a highly enriched water mixture that contains mostly deuterium oxide but also contains some ordinary water molecules as well: for instance heavy water used in CANDU reactors is 99.75% enriched by hydrogen atom-fraction. In comparison, in ordinary water, there are only about 156 deuterium atoms per million hydrogen atoms). In its pure form, it has a density about 11% greater than water, but otherwise, is physically and chemically similar. Heavy water is 10.6% denser than ordinary water, a difference which is not immediately obvious.
[20] A mirage occurs because of –
A.
Reflection by hot ground
B.
Total internal reflection by layers of air
C.
Interference of light
D.
Diffraction of light
Ans:
Total internal reflection by layers of air
Explanation :
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and "Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically-stacked images, which form one rapidly-changing mirage. Cold air is denser than warm air and has therefore a greater refractive index.
[21] Knot is a measure of –
A.
The speed of ship
B.
The curvature of spherical objects
C.
Solar radiation
D.
Intensity of earthquake shock
Ans:
The speed of ship
Explanation :
The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. There is no standard abbreviation but km is commonly used. The knot is a non-SI unit accepted for use with the International System of Units (SI).
[22] When the main switch of the house is put off it disconnects the –
A.
live wire only
B.
live wire and the earth wire
C.
live wire and the neutral wire
D.
earth wire and the neutral wire
Ans:
live wire and the neutral wire
Explanation :
Three wires enter most homes from the power pole—two "hot" wires and a third "neutral" wire. Each hot wire provides 120-volt current for conventional lights, receptacles, and appliances when paired with the neutral wire, which is normally kept at zero volts or "ground potential." When both, hot wires are used together with the neutral, they power large 240-volt appliances such as air conditioners and electric ovens. All the electric appliances stop working in a house when the main switch is put off because the electric circuit (the path where the electricity travels) gets opened.
[23] Negative feedback in amplifiers –
A.
increases bandwidth and decreases noise
B.
decreases bandwidth and decreases noise
C.
increases bandwidth and increases noise
D.
decreases bandwidth and increases noise
Ans:
increases bandwidth and decreases noise
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
The knot (pronounced not) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. There is no standard abbreviation but km is commonly used. The knot is a non-SI unit accepted for use with the International System of Units (SI).
[22] When the main switch of the house is put off it disconnects the –
A.
live wire only
B.
live wire and the earth wire
C.
live wire and the neutral wire
D.
earth wire and the neutral wire
Ans:
live wire and the neutral wire
Explanation :
Three wires enter most homes from the power pole—two "hot" wires and a third "neutral" wire. Each hot wire provides 120-volt current for conventional lights, receptacles, and appliances when paired with the neutral wire, which is normally kept at zero volts or "ground potential." When both, hot wires are used together with the neutral, they power large 240-volt appliances such as air conditioners and electric ovens. All the electric appliances stop working in a house when the main switch is put off because the electric circuit (the path where the electricity travels) gets opened.
[23] Negative feedback in amplifiers –
A.
increases bandwidth and decreases noise
B.
decreases bandwidth and decreases noise
C.
increases bandwidth and increases noise
D.
decreases bandwidth and increases noise
Ans:
increases bandwidth and decreases noise
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
Voltage gain, input impedance, output impedance, bandwidth etc. are few important characteristics of an amplifier. These parameters are more or less constant for a given amplifier. Quite often, the values of these parameters are required to be controlled. This can be conveniently achieved by employing a technique, called the feedback.
[24] What is Hooke's Law?
A.
Stress is inversely proportional to strain.
B.
Stress is directly proportional to strain.
C.
Stress and strain are dependent on each other.
D.
Stress and strain are independent of each other.
Ans:
Stress is directly proportional to strain.
Explanation :
Hooke's law is a principle of physics that states that the force (F) needed to extend or compress a spring by some distance X scales linearly with respect to that distance.
[25] Wollen clothes keep the body warm because –
A.
Wool increases the temperature of the body
B.
Wool is a had conductor
C.
Wool absorbs radiant heat from outer objects
D.
Wool rejects heat from the outer objects
Ans:
Wool is a had conductor
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.
Explanation :
It is just because woolen clothes have fibres and between those fibres air is trapped which reduces heat loss. Air reduces heat loss because it is an insulator or poor conductor of heat. Wool has seeral qualities that distinguish it from hair or fur: it is crimped, it is elastic, and it grows in staples (clusters) .Wool's scaling and crimp make it easier to spin the fleece by helping the individual fibers attach to each other, so they stay together. Because of the crimp, wool fabrics have a greater bulk than other textiles, and retain air, which causes the product to retain heat.