[1] An aircraft can perform aerobatic manoeuvres in a vertical loop because of-
A.
gravity
B.
centripetal force
C.
weight
D.
centrifugal force
Ans:
gravity
Explanation :
It happens because of gravity. A key feature of super maneuvering aircrafts is a high thrust-to-weight ratio; that is, the comparison of the force produced by the engines to the aircraft's weight, which is the force of gravity on the aircraft.
[2] A photostat machine works on –
A.
electromagnetic image making
B.
electrostatic image making
C.
magnetic image making
D.
thermal image making
Ans:
electrostatic image making
Explanation :
A photocopier uses electrostatic charge to produce a copy. The original document is placed onto a sheet of glass. An image of this page is projected onto a positively charged drum. The drum has a coating which conducts electricity when light falls on it. The parts of the drum which are lit by the projected image lose their electrostatic charge when they start to conduct.
[3] If a copper wire is increased to double its length, its resistance will become –
A.
four times
B.
one-fourth
C.
double
D.
half
Ans:
double
Explanation :
There is a direct relationship between the amount of resistance encountered by charge and the length of wire it must traverse. After all, if resistance occurs as the result of collisions between charge carriers and the atoms of the wire, then there is likely to be more collisions in a longer wire.
[4] In a diesel engine the high temperature needed to ignite the fuel is achieved by –
A.
using heat from exhaust
B.
the battery
C.
compressing air in the cylinders
D.
an electrical spark
Ans:
compressing air in the cylinders
Explanation :
Diesel engines use the heat of compressed air to ignite the fuel (intakes air, compresses it, then injects fuel). Diesel engines need high compression ratios to generate the high temperatures required for fuel auto ignition.
[5] Which of the following physical quantities changes or tends to change the state of rest or of uniform motion of a body in a straight line?
A.
Momentum
B.
Mass
C.
Force
D.
Inertia
Ans:
Force
Explanation :
Force is an agent which changes or tends to change the state of rest or of uniform motion of a body.
[6] Which of the following in the correct device that converts thermal energy into electrical energy?
A.
constant volume gas thermometer
B.
liquid-in-glass thermometer
C.
thermopile
D.
none of these
Ans:
thermopile
Explanation :
A thermopile is an electronic device that converts thermal energy into electrical energy. The thermal to electrical energy converting device may comprise a device exhibiting thermocouple or Seebeck effects, Peltier effects, Thomson effects and/or pyroelectricity effects.
[7] To measure the speed of an approaching car a police officer shines –
A.
light waves on it
B.
microwaves on it
C.
radio waves on it
D.
ultra high frequency waves on it
Ans:
radio waves on it
Explanation :
Radar, which stands for radio detection and ranging, is a system that uses reflected radio waves to detect objects and measure their distance and speed. For example, police use radar to calculate the speed of cars.
[8] A person wears spectators with concave lenses. It means that normally (when not using glasses), the image of distant objects is focused in his eyes –
A.
behind the retina
B.
in front of the retina
C.
on the retina
D.
on the blind spot
Ans:
in front of the retina
Explanation :
A concave lens is used to correct short-sightedness (myopia). In myopia, images are formed in front of the retina, resulting in a blurred image. This occurs when the eye is relatively too long or the refractive powers of the cornea and lens of the eye are relatively too strong.
[9] Ohm's law defines –
A.
a resistance
B.
current only
C.
voltage only
D.
both current and voltage
Ans:
a resistance
Explanation :
Ohm's law a law relating the voltage difference between two points, the electric current flowing between them, and the resistance of the path of the current.
[10] Lakes freeze in cold countries in winter, leaving the water underneath at –
A.
0°C
B.
0°F
C.
4°C
D.
4°F
Ans:
4°C
Explanation :
Lake ice cover is seasonal and occurs where average daily temperature is below the freezing point. Once formed the lake ice thickens over the course of the winter as the temperature gets colder. The lakes thermal structure prepares for ice with 0 (zero) degrees Celsius water at the surface and denser 4 degrees Celsius at the bottom.
[11] Which one of the following determines the sharpness of image in a camera?
A.
The aperture
B.
The exposure time
C.
The focal length of the lens
D.
Size of the camera
Ans:
The aperture
Explanation :
Image quality is a characteristic of an image that measures the perceived image degradation (typically, compared to an ideal or perfect image). Imaging systems may introduce some amounts of distortion or artifacts in the signal, so the quality assessment is an important problem. Sharpness determines the amount of detail an image can convey.
[12] Light from the Sun reaches us in nearly -
A.
2 minutes
B.
4 minutes
C.
8 minutes
D.
16 minutes
Ans:
8 minutes
Explanation :
The sun’s light takes about 8 minutes to reach the Earth after it has been emitted from the sun’s surface. The time it takes for light to reach planets in our Solar System (not the Milky Way, which is our galaxy) varies from about 3 minutes for Mercury, to about 5.3 hours for Pluto.
[13] Red data book contains data of which of the following?
A.
All plant species
B.
All animal species
C.
All endangered species
D.
All extinct species
Ans:
All endangered species
Explanation :
The Red Data Book is the state document established for documenting rare and endangered species of animals, plants and fungi as well as some local sub-species that exist within the territory of the state or country.
[14] Second’s pendulum is a pendulum which executes one oscillation in:
A.
Half a second
B.
One second
C.
Two seconds
D.
None of these
Ans:
Two seconds
Explanation :
A pendulum is a weight suspended from a pivot so that it can swing freely. A seconds pendulum is a pendulum whose period is precisely two seconds; one second for a swing in one direction and one second for the return swing, a frequency of 1/2 Hz.
[15] Which of the following is most elastic?
A.
Rubber
B.
Wet clay
C.
Steel
D.
Plastic
Ans:
Steel
Explanation :
In physics, elasticity is a physical property of materials which return to their original shape after the stress that caused their deformation is no longer applied. For very small deformations, most elastic materials, such as springs, exhibit linear elasticity. This means that they are characterized by a linear relationship between stress and strain (the relative amount of deformation).
[16] Sound cannot pass through –
A.
Water
B.
Steel
C.
Air
D.
Vacuum
Ans:
Vacuum
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. Sound also travels through plasma. Sound is a sequence of waves of pressure that propagates through compressible media such as air or water. (Sound can propagate through solids as well, but there are additional modes of propagation). Sound cannot travel through a vacuum because it does not provide the medium to propagate.
[17] The instrument used to measure the speed of the wind is –
A.
Altimeter
B.
Anemometer
C.
Chronometer
D.
Dosimeter
Ans:
Anemometer
Explanation :
An anemometer is a device for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, meaning wind, and is used to describe any airspeed measurement instrument used in meteorology or aerodynamics. The first known description of an anemometer was given by Leon Battista Alberti around 1450.
[18] An optically plane surface reflects a beam of light –
A.
as a parallel beam in one direction
B.
as diffused beams in all directions
C.
as parallel beams in all directions
D.
as a diffused beam in one direction
Ans:
as a parallel beam in one direction
Explanation :
An optically plane surface reflects a beam of light as a parallel beam in one direction. The set of incident rays are reflected as a set of rays. In other words, a beam of light is reflected as a beam of light if the mirror is plane and its reflecting surface is smooth. This type of reflection of a set of rays is called Specular Reflection.
[19] The slope of a velocity-time graph represents –
A.
acceleration
B.
displacement
C.
distance
D.
speed
Ans:
acceleration
Explanation :
A plot of velocity-time is used to determine the acceleration of an object (the slope). If the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). If the acceleration is negative, then the velocity-time graph is a downward sloping line (i.e., the slope is negative).
[20] The material which can be deformed permanently by heat and pressure is called a -
A.
thermoset
B.
thermoplastic
C.
chemical compound
D.
polymer
Ans:
thermoset
Explanation :
A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin.
[21] On planet Earth, there is no centrifugal force at the –
A.
Equator
B.
Tropic of Cancer
C.
Tropic of Capricorn
D.
Poles
Ans:
Poles
Explanation :
Some common examples of centrifugal force at work are mud flying off a tire and children feeling a force pushing them outwards while spinning on a roundabout.
[22] Gas thermometers are more sensitive than the liquid thermometers because of the gases -
A.
have low specific heat
B.
have high specific heat
C.
have large coefficient of expansion
D.
are lighter
Ans:
have low specific heat
Explanation :
Gas thermometers are more sensitive because gas has low specific heat than liquids. Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermometer.
[23] The earth-wire of a cable is connected to –
A.
the outer metallic body of the appliance
B.
the fuse of the appliance
C.
the filament of the appliance
D.
short circuitry of the appliance
Ans:
the fuse of the appliance
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
It happens because of gravity. A key feature of super maneuvering aircrafts is a high thrust-to-weight ratio; that is, the comparison of the force produced by the engines to the aircraft's weight, which is the force of gravity on the aircraft.
[2] A photostat machine works on –
A.
electromagnetic image making
B.
electrostatic image making
C.
magnetic image making
D.
thermal image making
Ans:
electrostatic image making
Explanation :
A photocopier uses electrostatic charge to produce a copy. The original document is placed onto a sheet of glass. An image of this page is projected onto a positively charged drum. The drum has a coating which conducts electricity when light falls on it. The parts of the drum which are lit by the projected image lose their electrostatic charge when they start to conduct.
[3] If a copper wire is increased to double its length, its resistance will become –
A.
four times
B.
one-fourth
C.
double
D.
half
Ans:
double
Explanation :
There is a direct relationship between the amount of resistance encountered by charge and the length of wire it must traverse. After all, if resistance occurs as the result of collisions between charge carriers and the atoms of the wire, then there is likely to be more collisions in a longer wire.
[4] In a diesel engine the high temperature needed to ignite the fuel is achieved by –
A.
using heat from exhaust
B.
the battery
C.
compressing air in the cylinders
D.
an electrical spark
Ans:
compressing air in the cylinders
Explanation :
Diesel engines use the heat of compressed air to ignite the fuel (intakes air, compresses it, then injects fuel). Diesel engines need high compression ratios to generate the high temperatures required for fuel auto ignition.
[5] Which of the following physical quantities changes or tends to change the state of rest or of uniform motion of a body in a straight line?
A.
Momentum
B.
Mass
C.
Force
D.
Inertia
Ans:
Force
Explanation :
Force is an agent which changes or tends to change the state of rest or of uniform motion of a body.
[6] Which of the following in the correct device that converts thermal energy into electrical energy?
A.
constant volume gas thermometer
B.
liquid-in-glass thermometer
C.
thermopile
D.
none of these
Ans:
thermopile
Explanation :
A thermopile is an electronic device that converts thermal energy into electrical energy. The thermal to electrical energy converting device may comprise a device exhibiting thermocouple or Seebeck effects, Peltier effects, Thomson effects and/or pyroelectricity effects.
[7] To measure the speed of an approaching car a police officer shines –
A.
light waves on it
B.
microwaves on it
C.
radio waves on it
D.
ultra high frequency waves on it
Ans:
radio waves on it
Explanation :
Radar, which stands for radio detection and ranging, is a system that uses reflected radio waves to detect objects and measure their distance and speed. For example, police use radar to calculate the speed of cars.
[8] A person wears spectators with concave lenses. It means that normally (when not using glasses), the image of distant objects is focused in his eyes –
A.
behind the retina
B.
in front of the retina
C.
on the retina
D.
on the blind spot
Ans:
in front of the retina
Explanation :
A concave lens is used to correct short-sightedness (myopia). In myopia, images are formed in front of the retina, resulting in a blurred image. This occurs when the eye is relatively too long or the refractive powers of the cornea and lens of the eye are relatively too strong.
[9] Ohm's law defines –
A.
a resistance
B.
current only
C.
voltage only
D.
both current and voltage
Ans:
a resistance
Explanation :
Ohm's law a law relating the voltage difference between two points, the electric current flowing between them, and the resistance of the path of the current.
[10] Lakes freeze in cold countries in winter, leaving the water underneath at –
A.
0°C
B.
0°F
C.
4°C
D.
4°F
Ans:
4°C
Explanation :
Lake ice cover is seasonal and occurs where average daily temperature is below the freezing point. Once formed the lake ice thickens over the course of the winter as the temperature gets colder. The lakes thermal structure prepares for ice with 0 (zero) degrees Celsius water at the surface and denser 4 degrees Celsius at the bottom.
[11] Which one of the following determines the sharpness of image in a camera?
A.
The aperture
B.
The exposure time
C.
The focal length of the lens
D.
Size of the camera
Ans:
The aperture
Explanation :
Image quality is a characteristic of an image that measures the perceived image degradation (typically, compared to an ideal or perfect image). Imaging systems may introduce some amounts of distortion or artifacts in the signal, so the quality assessment is an important problem. Sharpness determines the amount of detail an image can convey.
[12] Light from the Sun reaches us in nearly -
A.
2 minutes
B.
4 minutes
C.
8 minutes
D.
16 minutes
Ans:
8 minutes
Explanation :
The sun’s light takes about 8 minutes to reach the Earth after it has been emitted from the sun’s surface. The time it takes for light to reach planets in our Solar System (not the Milky Way, which is our galaxy) varies from about 3 minutes for Mercury, to about 5.3 hours for Pluto.
[13] Red data book contains data of which of the following?
A.
All plant species
B.
All animal species
C.
All endangered species
D.
All extinct species
Ans:
All endangered species
Explanation :
The Red Data Book is the state document established for documenting rare and endangered species of animals, plants and fungi as well as some local sub-species that exist within the territory of the state or country.
[14] Second’s pendulum is a pendulum which executes one oscillation in:
A.
Half a second
B.
One second
C.
Two seconds
D.
None of these
Ans:
Two seconds
Explanation :
A pendulum is a weight suspended from a pivot so that it can swing freely. A seconds pendulum is a pendulum whose period is precisely two seconds; one second for a swing in one direction and one second for the return swing, a frequency of 1/2 Hz.
[15] Which of the following is most elastic?
A.
Rubber
B.
Wet clay
C.
Steel
D.
Plastic
Ans:
Steel
Explanation :
In physics, elasticity is a physical property of materials which return to their original shape after the stress that caused their deformation is no longer applied. For very small deformations, most elastic materials, such as springs, exhibit linear elasticity. This means that they are characterized by a linear relationship between stress and strain (the relative amount of deformation).
[16] Sound cannot pass through –
A.
Water
B.
Steel
C.
Air
D.
Vacuum
Ans:
Vacuum
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. Sound also travels through plasma. Sound is a sequence of waves of pressure that propagates through compressible media such as air or water. (Sound can propagate through solids as well, but there are additional modes of propagation). Sound cannot travel through a vacuum because it does not provide the medium to propagate.
[17] The instrument used to measure the speed of the wind is –
A.
Altimeter
B.
Anemometer
C.
Chronometer
D.
Dosimeter
Ans:
Anemometer
Explanation :
An anemometer is a device for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, meaning wind, and is used to describe any airspeed measurement instrument used in meteorology or aerodynamics. The first known description of an anemometer was given by Leon Battista Alberti around 1450.
[18] An optically plane surface reflects a beam of light –
A.
as a parallel beam in one direction
B.
as diffused beams in all directions
C.
as parallel beams in all directions
D.
as a diffused beam in one direction
Ans:
as a parallel beam in one direction
Explanation :
An optically plane surface reflects a beam of light as a parallel beam in one direction. The set of incident rays are reflected as a set of rays. In other words, a beam of light is reflected as a beam of light if the mirror is plane and its reflecting surface is smooth. This type of reflection of a set of rays is called Specular Reflection.
[19] The slope of a velocity-time graph represents –
A.
acceleration
B.
displacement
C.
distance
D.
speed
Ans:
acceleration
Explanation :
A plot of velocity-time is used to determine the acceleration of an object (the slope). If the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). If the acceleration is negative, then the velocity-time graph is a downward sloping line (i.e., the slope is negative).
[20] The material which can be deformed permanently by heat and pressure is called a -
A.
thermoset
B.
thermoplastic
C.
chemical compound
D.
polymer
Ans:
thermoset
Explanation :
A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin.
[21] On planet Earth, there is no centrifugal force at the –
A.
Equator
B.
Tropic of Cancer
C.
Tropic of Capricorn
D.
Poles
Ans:
Poles
Explanation :
Some common examples of centrifugal force at work are mud flying off a tire and children feeling a force pushing them outwards while spinning on a roundabout.
[22] Gas thermometers are more sensitive than the liquid thermometers because of the gases -
A.
have low specific heat
B.
have high specific heat
C.
have large coefficient of expansion
D.
are lighter
Ans:
have low specific heat
Explanation :
Gas thermometers are more sensitive because gas has low specific heat than liquids. Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermometer.
[23] The earth-wire of a cable is connected to –
A.
the outer metallic body of the appliance
B.
the fuse of the appliance
C.
the filament of the appliance
D.
short circuitry of the appliance
Ans:
the fuse of the appliance
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
There is a direct relationship between the amount of resistance encountered by charge and the length of wire it must traverse. After all, if resistance occurs as the result of collisions between charge carriers and the atoms of the wire, then there is likely to be more collisions in a longer wire.
[4] In a diesel engine the high temperature needed to ignite the fuel is achieved by –
A.
using heat from exhaust
B.
the battery
C.
compressing air in the cylinders
D.
an electrical spark
Ans:
compressing air in the cylinders
Explanation :
Diesel engines use the heat of compressed air to ignite the fuel (intakes air, compresses it, then injects fuel). Diesel engines need high compression ratios to generate the high temperatures required for fuel auto ignition.
[5] Which of the following physical quantities changes or tends to change the state of rest or of uniform motion of a body in a straight line?
A.
Momentum
B.
Mass
C.
Force
D.
Inertia
Ans:
Force
Explanation :
Force is an agent which changes or tends to change the state of rest or of uniform motion of a body.
[6] Which of the following in the correct device that converts thermal energy into electrical energy?
A.
constant volume gas thermometer
B.
liquid-in-glass thermometer
C.
thermopile
D.
none of these
Ans:
thermopile
Explanation :
A thermopile is an electronic device that converts thermal energy into electrical energy. The thermal to electrical energy converting device may comprise a device exhibiting thermocouple or Seebeck effects, Peltier effects, Thomson effects and/or pyroelectricity effects.
[7] To measure the speed of an approaching car a police officer shines –
A.
light waves on it
B.
microwaves on it
C.
radio waves on it
D.
ultra high frequency waves on it
Ans:
radio waves on it
Explanation :
Radar, which stands for radio detection and ranging, is a system that uses reflected radio waves to detect objects and measure their distance and speed. For example, police use radar to calculate the speed of cars.
[8] A person wears spectators with concave lenses. It means that normally (when not using glasses), the image of distant objects is focused in his eyes –
A.
behind the retina
B.
in front of the retina
C.
on the retina
D.
on the blind spot
Ans:
in front of the retina
Explanation :
A concave lens is used to correct short-sightedness (myopia). In myopia, images are formed in front of the retina, resulting in a blurred image. This occurs when the eye is relatively too long or the refractive powers of the cornea and lens of the eye are relatively too strong.
[9] Ohm's law defines –
A.
a resistance
B.
current only
C.
voltage only
D.
both current and voltage
Ans:
a resistance
Explanation :
Ohm's law a law relating the voltage difference between two points, the electric current flowing between them, and the resistance of the path of the current.
[10] Lakes freeze in cold countries in winter, leaving the water underneath at –
A.
0°C
B.
0°F
C.
4°C
D.
4°F
Ans:
4°C
Explanation :
Lake ice cover is seasonal and occurs where average daily temperature is below the freezing point. Once formed the lake ice thickens over the course of the winter as the temperature gets colder. The lakes thermal structure prepares for ice with 0 (zero) degrees Celsius water at the surface and denser 4 degrees Celsius at the bottom.
[11] Which one of the following determines the sharpness of image in a camera?
A.
The aperture
B.
The exposure time
C.
The focal length of the lens
D.
Size of the camera
Ans:
The aperture
Explanation :
Image quality is a characteristic of an image that measures the perceived image degradation (typically, compared to an ideal or perfect image). Imaging systems may introduce some amounts of distortion or artifacts in the signal, so the quality assessment is an important problem. Sharpness determines the amount of detail an image can convey.
[12] Light from the Sun reaches us in nearly -
A.
2 minutes
B.
4 minutes
C.
8 minutes
D.
16 minutes
Ans:
8 minutes
Explanation :
The sun’s light takes about 8 minutes to reach the Earth after it has been emitted from the sun’s surface. The time it takes for light to reach planets in our Solar System (not the Milky Way, which is our galaxy) varies from about 3 minutes for Mercury, to about 5.3 hours for Pluto.
[13] Red data book contains data of which of the following?
A.
All plant species
B.
All animal species
C.
All endangered species
D.
All extinct species
Ans:
All endangered species
Explanation :
The Red Data Book is the state document established for documenting rare and endangered species of animals, plants and fungi as well as some local sub-species that exist within the territory of the state or country.
[14] Second’s pendulum is a pendulum which executes one oscillation in:
A.
Half a second
B.
One second
C.
Two seconds
D.
None of these
Ans:
Two seconds
Explanation :
A pendulum is a weight suspended from a pivot so that it can swing freely. A seconds pendulum is a pendulum whose period is precisely two seconds; one second for a swing in one direction and one second for the return swing, a frequency of 1/2 Hz.
[15] Which of the following is most elastic?
A.
Rubber
B.
Wet clay
C.
Steel
D.
Plastic
Ans:
Steel
Explanation :
In physics, elasticity is a physical property of materials which return to their original shape after the stress that caused their deformation is no longer applied. For very small deformations, most elastic materials, such as springs, exhibit linear elasticity. This means that they are characterized by a linear relationship between stress and strain (the relative amount of deformation).
[16] Sound cannot pass through –
A.
Water
B.
Steel
C.
Air
D.
Vacuum
Ans:
Vacuum
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. Sound also travels through plasma. Sound is a sequence of waves of pressure that propagates through compressible media such as air or water. (Sound can propagate through solids as well, but there are additional modes of propagation). Sound cannot travel through a vacuum because it does not provide the medium to propagate.
[17] The instrument used to measure the speed of the wind is –
A.
Altimeter
B.
Anemometer
C.
Chronometer
D.
Dosimeter
Ans:
Anemometer
Explanation :
An anemometer is a device for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, meaning wind, and is used to describe any airspeed measurement instrument used in meteorology or aerodynamics. The first known description of an anemometer was given by Leon Battista Alberti around 1450.
[18] An optically plane surface reflects a beam of light –
A.
as a parallel beam in one direction
B.
as diffused beams in all directions
C.
as parallel beams in all directions
D.
as a diffused beam in one direction
Ans:
as a parallel beam in one direction
Explanation :
An optically plane surface reflects a beam of light as a parallel beam in one direction. The set of incident rays are reflected as a set of rays. In other words, a beam of light is reflected as a beam of light if the mirror is plane and its reflecting surface is smooth. This type of reflection of a set of rays is called Specular Reflection.
[19] The slope of a velocity-time graph represents –
A.
acceleration
B.
displacement
C.
distance
D.
speed
Ans:
acceleration
Explanation :
A plot of velocity-time is used to determine the acceleration of an object (the slope). If the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). If the acceleration is negative, then the velocity-time graph is a downward sloping line (i.e., the slope is negative).
[20] The material which can be deformed permanently by heat and pressure is called a -
A.
thermoset
B.
thermoplastic
C.
chemical compound
D.
polymer
Ans:
thermoset
Explanation :
A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin.
[21] On planet Earth, there is no centrifugal force at the –
A.
Equator
B.
Tropic of Cancer
C.
Tropic of Capricorn
D.
Poles
Ans:
Poles
Explanation :
Some common examples of centrifugal force at work are mud flying off a tire and children feeling a force pushing them outwards while spinning on a roundabout.
[22] Gas thermometers are more sensitive than the liquid thermometers because of the gases -
A.
have low specific heat
B.
have high specific heat
C.
have large coefficient of expansion
D.
are lighter
Ans:
have low specific heat
Explanation :
Gas thermometers are more sensitive because gas has low specific heat than liquids. Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermometer.
[23] The earth-wire of a cable is connected to –
A.
the outer metallic body of the appliance
B.
the fuse of the appliance
C.
the filament of the appliance
D.
short circuitry of the appliance
Ans:
the fuse of the appliance
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
Force is an agent which changes or tends to change the state of rest or of uniform motion of a body.
[6] Which of the following in the correct device that converts thermal energy into electrical energy?
A.
constant volume gas thermometer
B.
liquid-in-glass thermometer
C.
thermopile
D.
none of these
Ans:
thermopile
Explanation :
A thermopile is an electronic device that converts thermal energy into electrical energy. The thermal to electrical energy converting device may comprise a device exhibiting thermocouple or Seebeck effects, Peltier effects, Thomson effects and/or pyroelectricity effects.
[7] To measure the speed of an approaching car a police officer shines –
A.
light waves on it
B.
microwaves on it
C.
radio waves on it
D.
ultra high frequency waves on it
Ans:
radio waves on it
Explanation :
Radar, which stands for radio detection and ranging, is a system that uses reflected radio waves to detect objects and measure their distance and speed. For example, police use radar to calculate the speed of cars.
[8] A person wears spectators with concave lenses. It means that normally (when not using glasses), the image of distant objects is focused in his eyes –
A.
behind the retina
B.
in front of the retina
C.
on the retina
D.
on the blind spot
Ans:
in front of the retina
Explanation :
A concave lens is used to correct short-sightedness (myopia). In myopia, images are formed in front of the retina, resulting in a blurred image. This occurs when the eye is relatively too long or the refractive powers of the cornea and lens of the eye are relatively too strong.
[9] Ohm's law defines –
A.
a resistance
B.
current only
C.
voltage only
D.
both current and voltage
Ans:
a resistance
Explanation :
Ohm's law a law relating the voltage difference between two points, the electric current flowing between them, and the resistance of the path of the current.
[10] Lakes freeze in cold countries in winter, leaving the water underneath at –
A.
0°C
B.
0°F
C.
4°C
D.
4°F
Ans:
4°C
Explanation :
Lake ice cover is seasonal and occurs where average daily temperature is below the freezing point. Once formed the lake ice thickens over the course of the winter as the temperature gets colder. The lakes thermal structure prepares for ice with 0 (zero) degrees Celsius water at the surface and denser 4 degrees Celsius at the bottom.
[11] Which one of the following determines the sharpness of image in a camera?
A.
The aperture
B.
The exposure time
C.
The focal length of the lens
D.
Size of the camera
Ans:
The aperture
Explanation :
Image quality is a characteristic of an image that measures the perceived image degradation (typically, compared to an ideal or perfect image). Imaging systems may introduce some amounts of distortion or artifacts in the signal, so the quality assessment is an important problem. Sharpness determines the amount of detail an image can convey.
[12] Light from the Sun reaches us in nearly -
A.
2 minutes
B.
4 minutes
C.
8 minutes
D.
16 minutes
Ans:
8 minutes
Explanation :
The sun’s light takes about 8 minutes to reach the Earth after it has been emitted from the sun’s surface. The time it takes for light to reach planets in our Solar System (not the Milky Way, which is our galaxy) varies from about 3 minutes for Mercury, to about 5.3 hours for Pluto.
[13] Red data book contains data of which of the following?
A.
All plant species
B.
All animal species
C.
All endangered species
D.
All extinct species
Ans:
All endangered species
Explanation :
The Red Data Book is the state document established for documenting rare and endangered species of animals, plants and fungi as well as some local sub-species that exist within the territory of the state or country.
[14] Second’s pendulum is a pendulum which executes one oscillation in:
A.
Half a second
B.
One second
C.
Two seconds
D.
None of these
Ans:
Two seconds
Explanation :
A pendulum is a weight suspended from a pivot so that it can swing freely. A seconds pendulum is a pendulum whose period is precisely two seconds; one second for a swing in one direction and one second for the return swing, a frequency of 1/2 Hz.
[15] Which of the following is most elastic?
A.
Rubber
B.
Wet clay
C.
Steel
D.
Plastic
Ans:
Steel
Explanation :
In physics, elasticity is a physical property of materials which return to their original shape after the stress that caused their deformation is no longer applied. For very small deformations, most elastic materials, such as springs, exhibit linear elasticity. This means that they are characterized by a linear relationship between stress and strain (the relative amount of deformation).
[16] Sound cannot pass through –
A.
Water
B.
Steel
C.
Air
D.
Vacuum
Ans:
Vacuum
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. Sound also travels through plasma. Sound is a sequence of waves of pressure that propagates through compressible media such as air or water. (Sound can propagate through solids as well, but there are additional modes of propagation). Sound cannot travel through a vacuum because it does not provide the medium to propagate.
[17] The instrument used to measure the speed of the wind is –
A.
Altimeter
B.
Anemometer
C.
Chronometer
D.
Dosimeter
Ans:
Anemometer
Explanation :
An anemometer is a device for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, meaning wind, and is used to describe any airspeed measurement instrument used in meteorology or aerodynamics. The first known description of an anemometer was given by Leon Battista Alberti around 1450.
[18] An optically plane surface reflects a beam of light –
A.
as a parallel beam in one direction
B.
as diffused beams in all directions
C.
as parallel beams in all directions
D.
as a diffused beam in one direction
Ans:
as a parallel beam in one direction
Explanation :
An optically plane surface reflects a beam of light as a parallel beam in one direction. The set of incident rays are reflected as a set of rays. In other words, a beam of light is reflected as a beam of light if the mirror is plane and its reflecting surface is smooth. This type of reflection of a set of rays is called Specular Reflection.
[19] The slope of a velocity-time graph represents –
A.
acceleration
B.
displacement
C.
distance
D.
speed
Ans:
acceleration
Explanation :
A plot of velocity-time is used to determine the acceleration of an object (the slope). If the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). If the acceleration is negative, then the velocity-time graph is a downward sloping line (i.e., the slope is negative).
[20] The material which can be deformed permanently by heat and pressure is called a -
A.
thermoset
B.
thermoplastic
C.
chemical compound
D.
polymer
Ans:
thermoset
Explanation :
A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin.
[21] On planet Earth, there is no centrifugal force at the –
A.
Equator
B.
Tropic of Cancer
C.
Tropic of Capricorn
D.
Poles
Ans:
Poles
Explanation :
Some common examples of centrifugal force at work are mud flying off a tire and children feeling a force pushing them outwards while spinning on a roundabout.
[22] Gas thermometers are more sensitive than the liquid thermometers because of the gases -
A.
have low specific heat
B.
have high specific heat
C.
have large coefficient of expansion
D.
are lighter
Ans:
have low specific heat
Explanation :
Gas thermometers are more sensitive because gas has low specific heat than liquids. Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermometer.
[23] The earth-wire of a cable is connected to –
A.
the outer metallic body of the appliance
B.
the fuse of the appliance
C.
the filament of the appliance
D.
short circuitry of the appliance
Ans:
the fuse of the appliance
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
Radar, which stands for radio detection and ranging, is a system that uses reflected radio waves to detect objects and measure their distance and speed. For example, police use radar to calculate the speed of cars.
[8] A person wears spectators with concave lenses. It means that normally (when not using glasses), the image of distant objects is focused in his eyes –
A.
behind the retina
B.
in front of the retina
C.
on the retina
D.
on the blind spot
Ans:
in front of the retina
Explanation :
A concave lens is used to correct short-sightedness (myopia). In myopia, images are formed in front of the retina, resulting in a blurred image. This occurs when the eye is relatively too long or the refractive powers of the cornea and lens of the eye are relatively too strong.
[9] Ohm's law defines –
A.
a resistance
B.
current only
C.
voltage only
D.
both current and voltage
Ans:
a resistance
Explanation :
Ohm's law a law relating the voltage difference between two points, the electric current flowing between them, and the resistance of the path of the current.
[10] Lakes freeze in cold countries in winter, leaving the water underneath at –
A.
0°C
B.
0°F
C.
4°C
D.
4°F
Ans:
4°C
Explanation :
Lake ice cover is seasonal and occurs where average daily temperature is below the freezing point. Once formed the lake ice thickens over the course of the winter as the temperature gets colder. The lakes thermal structure prepares for ice with 0 (zero) degrees Celsius water at the surface and denser 4 degrees Celsius at the bottom.
[11] Which one of the following determines the sharpness of image in a camera?
A.
The aperture
B.
The exposure time
C.
The focal length of the lens
D.
Size of the camera
Ans:
The aperture
Explanation :
Image quality is a characteristic of an image that measures the perceived image degradation (typically, compared to an ideal or perfect image). Imaging systems may introduce some amounts of distortion or artifacts in the signal, so the quality assessment is an important problem. Sharpness determines the amount of detail an image can convey.
[12] Light from the Sun reaches us in nearly -
A.
2 minutes
B.
4 minutes
C.
8 minutes
D.
16 minutes
Ans:
8 minutes
Explanation :
The sun’s light takes about 8 minutes to reach the Earth after it has been emitted from the sun’s surface. The time it takes for light to reach planets in our Solar System (not the Milky Way, which is our galaxy) varies from about 3 minutes for Mercury, to about 5.3 hours for Pluto.
[13] Red data book contains data of which of the following?
A.
All plant species
B.
All animal species
C.
All endangered species
D.
All extinct species
Ans:
All endangered species
Explanation :
The Red Data Book is the state document established for documenting rare and endangered species of animals, plants and fungi as well as some local sub-species that exist within the territory of the state or country.
[14] Second’s pendulum is a pendulum which executes one oscillation in:
A.
Half a second
B.
One second
C.
Two seconds
D.
None of these
Ans:
Two seconds
Explanation :
A pendulum is a weight suspended from a pivot so that it can swing freely. A seconds pendulum is a pendulum whose period is precisely two seconds; one second for a swing in one direction and one second for the return swing, a frequency of 1/2 Hz.
[15] Which of the following is most elastic?
A.
Rubber
B.
Wet clay
C.
Steel
D.
Plastic
Ans:
Steel
Explanation :
In physics, elasticity is a physical property of materials which return to their original shape after the stress that caused their deformation is no longer applied. For very small deformations, most elastic materials, such as springs, exhibit linear elasticity. This means that they are characterized by a linear relationship between stress and strain (the relative amount of deformation).
[16] Sound cannot pass through –
A.
Water
B.
Steel
C.
Air
D.
Vacuum
Ans:
Vacuum
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. Sound also travels through plasma. Sound is a sequence of waves of pressure that propagates through compressible media such as air or water. (Sound can propagate through solids as well, but there are additional modes of propagation). Sound cannot travel through a vacuum because it does not provide the medium to propagate.
[17] The instrument used to measure the speed of the wind is –
A.
Altimeter
B.
Anemometer
C.
Chronometer
D.
Dosimeter
Ans:
Anemometer
Explanation :
An anemometer is a device for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, meaning wind, and is used to describe any airspeed measurement instrument used in meteorology or aerodynamics. The first known description of an anemometer was given by Leon Battista Alberti around 1450.
[18] An optically plane surface reflects a beam of light –
A.
as a parallel beam in one direction
B.
as diffused beams in all directions
C.
as parallel beams in all directions
D.
as a diffused beam in one direction
Ans:
as a parallel beam in one direction
Explanation :
An optically plane surface reflects a beam of light as a parallel beam in one direction. The set of incident rays are reflected as a set of rays. In other words, a beam of light is reflected as a beam of light if the mirror is plane and its reflecting surface is smooth. This type of reflection of a set of rays is called Specular Reflection.
[19] The slope of a velocity-time graph represents –
A.
acceleration
B.
displacement
C.
distance
D.
speed
Ans:
acceleration
Explanation :
A plot of velocity-time is used to determine the acceleration of an object (the slope). If the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). If the acceleration is negative, then the velocity-time graph is a downward sloping line (i.e., the slope is negative).
[20] The material which can be deformed permanently by heat and pressure is called a -
A.
thermoset
B.
thermoplastic
C.
chemical compound
D.
polymer
Ans:
thermoset
Explanation :
A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin.
[21] On planet Earth, there is no centrifugal force at the –
A.
Equator
B.
Tropic of Cancer
C.
Tropic of Capricorn
D.
Poles
Ans:
Poles
Explanation :
Some common examples of centrifugal force at work are mud flying off a tire and children feeling a force pushing them outwards while spinning on a roundabout.
[22] Gas thermometers are more sensitive than the liquid thermometers because of the gases -
A.
have low specific heat
B.
have high specific heat
C.
have large coefficient of expansion
D.
are lighter
Ans:
have low specific heat
Explanation :
Gas thermometers are more sensitive because gas has low specific heat than liquids. Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermometer.
[23] The earth-wire of a cable is connected to –
A.
the outer metallic body of the appliance
B.
the fuse of the appliance
C.
the filament of the appliance
D.
short circuitry of the appliance
Ans:
the fuse of the appliance
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
Ohm's law a law relating the voltage difference between two points, the electric current flowing between them, and the resistance of the path of the current.
[10] Lakes freeze in cold countries in winter, leaving the water underneath at –
A.
0°C
B.
0°F
C.
4°C
D.
4°F
Ans:
4°C
Explanation :
Lake ice cover is seasonal and occurs where average daily temperature is below the freezing point. Once formed the lake ice thickens over the course of the winter as the temperature gets colder. The lakes thermal structure prepares for ice with 0 (zero) degrees Celsius water at the surface and denser 4 degrees Celsius at the bottom.
[11] Which one of the following determines the sharpness of image in a camera?
A.
The aperture
B.
The exposure time
C.
The focal length of the lens
D.
Size of the camera
Ans:
The aperture
Explanation :
Image quality is a characteristic of an image that measures the perceived image degradation (typically, compared to an ideal or perfect image). Imaging systems may introduce some amounts of distortion or artifacts in the signal, so the quality assessment is an important problem. Sharpness determines the amount of detail an image can convey.
[12] Light from the Sun reaches us in nearly -
A.
2 minutes
B.
4 minutes
C.
8 minutes
D.
16 minutes
Ans:
8 minutes
Explanation :
The sun’s light takes about 8 minutes to reach the Earth after it has been emitted from the sun’s surface. The time it takes for light to reach planets in our Solar System (not the Milky Way, which is our galaxy) varies from about 3 minutes for Mercury, to about 5.3 hours for Pluto.
[13] Red data book contains data of which of the following?
A.
All plant species
B.
All animal species
C.
All endangered species
D.
All extinct species
Ans:
All endangered species
Explanation :
The Red Data Book is the state document established for documenting rare and endangered species of animals, plants and fungi as well as some local sub-species that exist within the territory of the state or country.
[14] Second’s pendulum is a pendulum which executes one oscillation in:
A.
Half a second
B.
One second
C.
Two seconds
D.
None of these
Ans:
Two seconds
Explanation :
A pendulum is a weight suspended from a pivot so that it can swing freely. A seconds pendulum is a pendulum whose period is precisely two seconds; one second for a swing in one direction and one second for the return swing, a frequency of 1/2 Hz.
[15] Which of the following is most elastic?
A.
Rubber
B.
Wet clay
C.
Steel
D.
Plastic
Ans:
Steel
Explanation :
In physics, elasticity is a physical property of materials which return to their original shape after the stress that caused their deformation is no longer applied. For very small deformations, most elastic materials, such as springs, exhibit linear elasticity. This means that they are characterized by a linear relationship between stress and strain (the relative amount of deformation).
[16] Sound cannot pass through –
A.
Water
B.
Steel
C.
Air
D.
Vacuum
Ans:
Vacuum
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. Sound also travels through plasma. Sound is a sequence of waves of pressure that propagates through compressible media such as air or water. (Sound can propagate through solids as well, but there are additional modes of propagation). Sound cannot travel through a vacuum because it does not provide the medium to propagate.
[17] The instrument used to measure the speed of the wind is –
A.
Altimeter
B.
Anemometer
C.
Chronometer
D.
Dosimeter
Ans:
Anemometer
Explanation :
An anemometer is a device for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, meaning wind, and is used to describe any airspeed measurement instrument used in meteorology or aerodynamics. The first known description of an anemometer was given by Leon Battista Alberti around 1450.
[18] An optically plane surface reflects a beam of light –
A.
as a parallel beam in one direction
B.
as diffused beams in all directions
C.
as parallel beams in all directions
D.
as a diffused beam in one direction
Ans:
as a parallel beam in one direction
Explanation :
An optically plane surface reflects a beam of light as a parallel beam in one direction. The set of incident rays are reflected as a set of rays. In other words, a beam of light is reflected as a beam of light if the mirror is plane and its reflecting surface is smooth. This type of reflection of a set of rays is called Specular Reflection.
[19] The slope of a velocity-time graph represents –
A.
acceleration
B.
displacement
C.
distance
D.
speed
Ans:
acceleration
Explanation :
A plot of velocity-time is used to determine the acceleration of an object (the slope). If the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). If the acceleration is negative, then the velocity-time graph is a downward sloping line (i.e., the slope is negative).
[20] The material which can be deformed permanently by heat and pressure is called a -
A.
thermoset
B.
thermoplastic
C.
chemical compound
D.
polymer
Ans:
thermoset
Explanation :
A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin.
[21] On planet Earth, there is no centrifugal force at the –
A.
Equator
B.
Tropic of Cancer
C.
Tropic of Capricorn
D.
Poles
Ans:
Poles
Explanation :
Some common examples of centrifugal force at work are mud flying off a tire and children feeling a force pushing them outwards while spinning on a roundabout.
[22] Gas thermometers are more sensitive than the liquid thermometers because of the gases -
A.
have low specific heat
B.
have high specific heat
C.
have large coefficient of expansion
D.
are lighter
Ans:
have low specific heat
Explanation :
Gas thermometers are more sensitive because gas has low specific heat than liquids. Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermometer.
[23] The earth-wire of a cable is connected to –
A.
the outer metallic body of the appliance
B.
the fuse of the appliance
C.
the filament of the appliance
D.
short circuitry of the appliance
Ans:
the fuse of the appliance
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
Image quality is a characteristic of an image that measures the perceived image degradation (typically, compared to an ideal or perfect image). Imaging systems may introduce some amounts of distortion or artifacts in the signal, so the quality assessment is an important problem. Sharpness determines the amount of detail an image can convey.
[12] Light from the Sun reaches us in nearly -
A.
2 minutes
B.
4 minutes
C.
8 minutes
D.
16 minutes
Ans:
8 minutes
Explanation :
The sun’s light takes about 8 minutes to reach the Earth after it has been emitted from the sun’s surface. The time it takes for light to reach planets in our Solar System (not the Milky Way, which is our galaxy) varies from about 3 minutes for Mercury, to about 5.3 hours for Pluto.
[13] Red data book contains data of which of the following?
A.
All plant species
B.
All animal species
C.
All endangered species
D.
All extinct species
Ans:
All endangered species
Explanation :
The Red Data Book is the state document established for documenting rare and endangered species of animals, plants and fungi as well as some local sub-species that exist within the territory of the state or country.
[14] Second’s pendulum is a pendulum which executes one oscillation in:
A.
Half a second
B.
One second
C.
Two seconds
D.
None of these
Ans:
Two seconds
Explanation :
A pendulum is a weight suspended from a pivot so that it can swing freely. A seconds pendulum is a pendulum whose period is precisely two seconds; one second for a swing in one direction and one second for the return swing, a frequency of 1/2 Hz.
[15] Which of the following is most elastic?
A.
Rubber
B.
Wet clay
C.
Steel
D.
Plastic
Ans:
Steel
Explanation :
In physics, elasticity is a physical property of materials which return to their original shape after the stress that caused their deformation is no longer applied. For very small deformations, most elastic materials, such as springs, exhibit linear elasticity. This means that they are characterized by a linear relationship between stress and strain (the relative amount of deformation).
[16] Sound cannot pass through –
A.
Water
B.
Steel
C.
Air
D.
Vacuum
Ans:
Vacuum
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. Sound also travels through plasma. Sound is a sequence of waves of pressure that propagates through compressible media such as air or water. (Sound can propagate through solids as well, but there are additional modes of propagation). Sound cannot travel through a vacuum because it does not provide the medium to propagate.
[17] The instrument used to measure the speed of the wind is –
A.
Altimeter
B.
Anemometer
C.
Chronometer
D.
Dosimeter
Ans:
Anemometer
Explanation :
An anemometer is a device for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, meaning wind, and is used to describe any airspeed measurement instrument used in meteorology or aerodynamics. The first known description of an anemometer was given by Leon Battista Alberti around 1450.
[18] An optically plane surface reflects a beam of light –
A.
as a parallel beam in one direction
B.
as diffused beams in all directions
C.
as parallel beams in all directions
D.
as a diffused beam in one direction
Ans:
as a parallel beam in one direction
Explanation :
An optically plane surface reflects a beam of light as a parallel beam in one direction. The set of incident rays are reflected as a set of rays. In other words, a beam of light is reflected as a beam of light if the mirror is plane and its reflecting surface is smooth. This type of reflection of a set of rays is called Specular Reflection.
[19] The slope of a velocity-time graph represents –
A.
acceleration
B.
displacement
C.
distance
D.
speed
Ans:
acceleration
Explanation :
A plot of velocity-time is used to determine the acceleration of an object (the slope). If the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). If the acceleration is negative, then the velocity-time graph is a downward sloping line (i.e., the slope is negative).
[20] The material which can be deformed permanently by heat and pressure is called a -
A.
thermoset
B.
thermoplastic
C.
chemical compound
D.
polymer
Ans:
thermoset
Explanation :
A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin.
[21] On planet Earth, there is no centrifugal force at the –
A.
Equator
B.
Tropic of Cancer
C.
Tropic of Capricorn
D.
Poles
Ans:
Poles
Explanation :
Some common examples of centrifugal force at work are mud flying off a tire and children feeling a force pushing them outwards while spinning on a roundabout.
[22] Gas thermometers are more sensitive than the liquid thermometers because of the gases -
A.
have low specific heat
B.
have high specific heat
C.
have large coefficient of expansion
D.
are lighter
Ans:
have low specific heat
Explanation :
Gas thermometers are more sensitive because gas has low specific heat than liquids. Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermometer.
[23] The earth-wire of a cable is connected to –
A.
the outer metallic body of the appliance
B.
the fuse of the appliance
C.
the filament of the appliance
D.
short circuitry of the appliance
Ans:
the fuse of the appliance
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
The Red Data Book is the state document established for documenting rare and endangered species of animals, plants and fungi as well as some local sub-species that exist within the territory of the state or country.
[14] Second’s pendulum is a pendulum which executes one oscillation in:
A.
Half a second
B.
One second
C.
Two seconds
D.
None of these
Ans:
Two seconds
Explanation :
A pendulum is a weight suspended from a pivot so that it can swing freely. A seconds pendulum is a pendulum whose period is precisely two seconds; one second for a swing in one direction and one second for the return swing, a frequency of 1/2 Hz.
[15] Which of the following is most elastic?
A.
Rubber
B.
Wet clay
C.
Steel
D.
Plastic
Ans:
Steel
Explanation :
In physics, elasticity is a physical property of materials which return to their original shape after the stress that caused their deformation is no longer applied. For very small deformations, most elastic materials, such as springs, exhibit linear elasticity. This means that they are characterized by a linear relationship between stress and strain (the relative amount of deformation).
[16] Sound cannot pass through –
A.
Water
B.
Steel
C.
Air
D.
Vacuum
Ans:
Vacuum
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. Sound also travels through plasma. Sound is a sequence of waves of pressure that propagates through compressible media such as air or water. (Sound can propagate through solids as well, but there are additional modes of propagation). Sound cannot travel through a vacuum because it does not provide the medium to propagate.
[17] The instrument used to measure the speed of the wind is –
A.
Altimeter
B.
Anemometer
C.
Chronometer
D.
Dosimeter
Ans:
Anemometer
Explanation :
An anemometer is a device for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, meaning wind, and is used to describe any airspeed measurement instrument used in meteorology or aerodynamics. The first known description of an anemometer was given by Leon Battista Alberti around 1450.
[18] An optically plane surface reflects a beam of light –
A.
as a parallel beam in one direction
B.
as diffused beams in all directions
C.
as parallel beams in all directions
D.
as a diffused beam in one direction
Ans:
as a parallel beam in one direction
Explanation :
An optically plane surface reflects a beam of light as a parallel beam in one direction. The set of incident rays are reflected as a set of rays. In other words, a beam of light is reflected as a beam of light if the mirror is plane and its reflecting surface is smooth. This type of reflection of a set of rays is called Specular Reflection.
[19] The slope of a velocity-time graph represents –
A.
acceleration
B.
displacement
C.
distance
D.
speed
Ans:
acceleration
Explanation :
A plot of velocity-time is used to determine the acceleration of an object (the slope). If the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). If the acceleration is negative, then the velocity-time graph is a downward sloping line (i.e., the slope is negative).
[20] The material which can be deformed permanently by heat and pressure is called a -
A.
thermoset
B.
thermoplastic
C.
chemical compound
D.
polymer
Ans:
thermoset
Explanation :
A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin.
[21] On planet Earth, there is no centrifugal force at the –
A.
Equator
B.
Tropic of Cancer
C.
Tropic of Capricorn
D.
Poles
Ans:
Poles
Explanation :
Some common examples of centrifugal force at work are mud flying off a tire and children feeling a force pushing them outwards while spinning on a roundabout.
[22] Gas thermometers are more sensitive than the liquid thermometers because of the gases -
A.
have low specific heat
B.
have high specific heat
C.
have large coefficient of expansion
D.
are lighter
Ans:
have low specific heat
Explanation :
Gas thermometers are more sensitive because gas has low specific heat than liquids. Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermometer.
[23] The earth-wire of a cable is connected to –
A.
the outer metallic body of the appliance
B.
the fuse of the appliance
C.
the filament of the appliance
D.
short circuitry of the appliance
Ans:
the fuse of the appliance
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
In physics, elasticity is a physical property of materials which return to their original shape after the stress that caused their deformation is no longer applied. For very small deformations, most elastic materials, such as springs, exhibit linear elasticity. This means that they are characterized by a linear relationship between stress and strain (the relative amount of deformation).
[16] Sound cannot pass through –
A.
Water
B.
Steel
C.
Air
D.
Vacuum
Ans:
Vacuum
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. Sound also travels through plasma. Sound is a sequence of waves of pressure that propagates through compressible media such as air or water. (Sound can propagate through solids as well, but there are additional modes of propagation). Sound cannot travel through a vacuum because it does not provide the medium to propagate.
[17] The instrument used to measure the speed of the wind is –
A.
Altimeter
B.
Anemometer
C.
Chronometer
D.
Dosimeter
Ans:
Anemometer
Explanation :
An anemometer is a device for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, meaning wind, and is used to describe any airspeed measurement instrument used in meteorology or aerodynamics. The first known description of an anemometer was given by Leon Battista Alberti around 1450.
[18] An optically plane surface reflects a beam of light –
A.
as a parallel beam in one direction
B.
as diffused beams in all directions
C.
as parallel beams in all directions
D.
as a diffused beam in one direction
Ans:
as a parallel beam in one direction
Explanation :
An optically plane surface reflects a beam of light as a parallel beam in one direction. The set of incident rays are reflected as a set of rays. In other words, a beam of light is reflected as a beam of light if the mirror is plane and its reflecting surface is smooth. This type of reflection of a set of rays is called Specular Reflection.
[19] The slope of a velocity-time graph represents –
A.
acceleration
B.
displacement
C.
distance
D.
speed
Ans:
acceleration
Explanation :
A plot of velocity-time is used to determine the acceleration of an object (the slope). If the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). If the acceleration is negative, then the velocity-time graph is a downward sloping line (i.e., the slope is negative).
[20] The material which can be deformed permanently by heat and pressure is called a -
A.
thermoset
B.
thermoplastic
C.
chemical compound
D.
polymer
Ans:
thermoset
Explanation :
A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin.
[21] On planet Earth, there is no centrifugal force at the –
A.
Equator
B.
Tropic of Cancer
C.
Tropic of Capricorn
D.
Poles
Ans:
Poles
Explanation :
Some common examples of centrifugal force at work are mud flying off a tire and children feeling a force pushing them outwards while spinning on a roundabout.
[22] Gas thermometers are more sensitive than the liquid thermometers because of the gases -
A.
have low specific heat
B.
have high specific heat
C.
have large coefficient of expansion
D.
are lighter
Ans:
have low specific heat
Explanation :
Gas thermometers are more sensitive because gas has low specific heat than liquids. Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermometer.
[23] The earth-wire of a cable is connected to –
A.
the outer metallic body of the appliance
B.
the fuse of the appliance
C.
the filament of the appliance
D.
short circuitry of the appliance
Ans:
the fuse of the appliance
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
An anemometer is a device for measuring wind speed, and is a common weather station instrument. The term is derived from the Greek word anemos, meaning wind, and is used to describe any airspeed measurement instrument used in meteorology or aerodynamics. The first known description of an anemometer was given by Leon Battista Alberti around 1450.
[18] An optically plane surface reflects a beam of light –
A.
as a parallel beam in one direction
B.
as diffused beams in all directions
C.
as parallel beams in all directions
D.
as a diffused beam in one direction
Ans:
as a parallel beam in one direction
Explanation :
An optically plane surface reflects a beam of light as a parallel beam in one direction. The set of incident rays are reflected as a set of rays. In other words, a beam of light is reflected as a beam of light if the mirror is plane and its reflecting surface is smooth. This type of reflection of a set of rays is called Specular Reflection.
[19] The slope of a velocity-time graph represents –
A.
acceleration
B.
displacement
C.
distance
D.
speed
Ans:
acceleration
Explanation :
A plot of velocity-time is used to determine the acceleration of an object (the slope). If the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). If the acceleration is negative, then the velocity-time graph is a downward sloping line (i.e., the slope is negative).
[20] The material which can be deformed permanently by heat and pressure is called a -
A.
thermoset
B.
thermoplastic
C.
chemical compound
D.
polymer
Ans:
thermoset
Explanation :
A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin.
[21] On planet Earth, there is no centrifugal force at the –
A.
Equator
B.
Tropic of Cancer
C.
Tropic of Capricorn
D.
Poles
Ans:
Poles
Explanation :
Some common examples of centrifugal force at work are mud flying off a tire and children feeling a force pushing them outwards while spinning on a roundabout.
[22] Gas thermometers are more sensitive than the liquid thermometers because of the gases -
A.
have low specific heat
B.
have high specific heat
C.
have large coefficient of expansion
D.
are lighter
Ans:
have low specific heat
Explanation :
Gas thermometers are more sensitive because gas has low specific heat than liquids. Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermometer.
[23] The earth-wire of a cable is connected to –
A.
the outer metallic body of the appliance
B.
the fuse of the appliance
C.
the filament of the appliance
D.
short circuitry of the appliance
Ans:
the fuse of the appliance
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
A plot of velocity-time is used to determine the acceleration of an object (the slope). If the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). If the acceleration is negative, then the velocity-time graph is a downward sloping line (i.e., the slope is negative).
[20] The material which can be deformed permanently by heat and pressure is called a -
A.
thermoset
B.
thermoplastic
C.
chemical compound
D.
polymer
Ans:
thermoset
Explanation :
A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin.
[21] On planet Earth, there is no centrifugal force at the –
A.
Equator
B.
Tropic of Cancer
C.
Tropic of Capricorn
D.
Poles
Ans:
Poles
Explanation :
Some common examples of centrifugal force at work are mud flying off a tire and children feeling a force pushing them outwards while spinning on a roundabout.
[22] Gas thermometers are more sensitive than the liquid thermometers because of the gases -
A.
have low specific heat
B.
have high specific heat
C.
have large coefficient of expansion
D.
are lighter
Ans:
have low specific heat
Explanation :
Gas thermometers are more sensitive because gas has low specific heat than liquids. Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermometer.
[23] The earth-wire of a cable is connected to –
A.
the outer metallic body of the appliance
B.
the fuse of the appliance
C.
the filament of the appliance
D.
short circuitry of the appliance
Ans:
the fuse of the appliance
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
Some common examples of centrifugal force at work are mud flying off a tire and children feeling a force pushing them outwards while spinning on a roundabout.
[22] Gas thermometers are more sensitive than the liquid thermometers because of the gases -
A.
have low specific heat
B.
have high specific heat
C.
have large coefficient of expansion
D.
are lighter
Ans:
have low specific heat
Explanation :
Gas thermometers are more sensitive because gas has low specific heat than liquids. Gases are more sensitive to the temperature than liquids (such as mercury). That means gas expands more than the mercury for the same increase of temperature. Hence the gas thermometer is more sensitive than liquid (mercury) thermometer.
[23] The earth-wire of a cable is connected to –
A.
the outer metallic body of the appliance
B.
the fuse of the appliance
C.
the filament of the appliance
D.
short circuitry of the appliance
Ans:
the fuse of the appliance
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
Earth wire prevents Electric shocks. It is connected to the electrical cable of an appliance to prevent electric shocks. Actually it has very low resistance and allows current to pass through it easily.
[24] The best conductor of heat among the following is –
A.
alcohol
B.
mercury
C.
ether
D.
water
Ans:
mercury
Explanation :
Since mercury is 13+ times as dense as water, a given volume of mercury would carry about 4.4 times as much heat, so mercury is best conductor of heat among the given options. It is the only metal that is liquid at standard conditions for temperature and pressure. Mercury has one of the narrowest ranges of its liquid state of any metal.
[25] The metal used to make lightning conductors is –
A.
Iron
B.
Aluminum
C.
Copper
D.
Zinc
Ans:
Copper
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
Explanation :
A lightning rod is a metal rod or metallic object mounted on top of a building, electrically bonded using a wire or electrical conductor to interface with ground or "earth" through an electrode, engineered to protect the building in the event of lightning strike. If lightning targets the building it will preferentially strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.