[1] Convex mirrors are used as a rear view mirror in motor cycles because
A.
it forms real image
B.
it forms erect (upright) image
C.
it forms smaller image as compared with object
D.
All of the above
Ans:
it forms smaller image as compared with object
Explanation :
It is because image formed by an convex mirror is always virtual, erect and smaller than the object.
[2] Railway tracks are banked on curves so that –
A.
Necessary centrifugal force may be obtained from the horizontal component of the weight of the train
B.
No frictional force may be produced between the tracks and the wheels of the train
C.
Necessary centripetal force may be obtained from the horizontal component of the weight of the train
D.
The train may not fall down inwards
Ans:
Necessary centripetal force may be obtained from the horizontal component of the weight of the train
Explanation :
Railway tracks are banked on curves so that necessary centripetal force may be obtained from the horizontal component of the weight of the train. It helps the train to stay on the track as it negotiates the curve. The raised track provides required centripetal force to enable it to move round the curve.
[3] What is the range of mercury thermometer?
A.
0 degree Celsius to 350 degree Celsius
B.
-10 degree Celsius to 350 degree Celsius
C.
-20 degree Celsius to 350 degree Celsius
D.
-30 degree Celsius to 350 degree Celsius
Ans:
-30 degree Celsius to 350 degree Celsius
Explanation :
[4] The width of depletion layer of a P-N junction –
A.
decreases with light doping
B.
increases with heavy doping
C.
is independent of applied voltage
D.
is increased under reverse bias
Ans:
is increased under reverse bias
Explanation :
The total width of the depletion region is a function of applied reverse-bias and impurity concentration. Forward bias decreases the depletion region width whilst reverse bias increases it.
[5] Ventilators are provided near the ceiling of the room because –
A.
the exhaled warmer air rises up and goes out
B.
these provide cross ventilation in the room
C.
these provide some sunlight in the room
D.
these do not look nice in the lower part
Ans:
the exhaled warmer air rises up and goes out
Explanation :
Ventilation is a room air distribution strategy where conditioned outdoor air is supplied at floor level and extracted above the occupied zone, usually at ceiling height. A typical displacement ventilation system, such as one in an office space, supplies conditioned cool air from an air handling unit (AHU) through a low induction diffuser. The cool air spreads through the floor of the space and then rises as the air warms due to heat exchange with heat sources in the space (e.g., occupants, computers, lights).
[6] What Is a neuron?
A.
Basic unit of energy
B.
Particle released during radioactivity
C.
The anti-particle of neutron
D.
Basle unit of nervous system
Ans:
Basle unit of nervous system
Explanation :
A neuron is a nerve cell that is the basic building block of the nervous system. Neurons are specialized to transmit information throughout the body. These highly specialized nerve cells are responsible for communicating information in both chemical and electrical forms.
[7] Which of the following is not caused by atmospheric refraction of light?
A.
Sun appearing red at sunset
B.
Twinkling of stars at night
C.
Sun appearing higher in the sky than it actually is
D.
Sun becoming visible two or three minutes before actual sunrise
Ans:
Sun appearing higher in the sky than it actually is
Explanation :
The twinkling of stars and variation in size of the Sun are due to atmospheric refraction of light. Besides, refraction is also responsible for the sun to look during sunset and suntise. It is also responsible for the sun becoming two or three minutes before actual sunrise. The sun appears higher or lower in the sky due to the changing position of the Earth relative to the Sun.
[8] Why the needle of iron swims on water surface when it is kept gently?
A.
It will remain under the water, when it will displace more water than its weight
B.
the density of needle is less than that of water
C.
due to surface tension
D.
due to its shape
Ans:
due to surface tension
Explanation :
According to Archimedes principle and we can note that the amount of water displaced by a needle is lesser than the amount of water moved out by the needle (that is displacement of the needle). So the needle initially stays on the surface of the water and then sinks into the water. Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force.
[9] In which of the following cases, kinetic energy is being used in performing work?
A.
Paddling the bicycle to cover a distance
B.
Driving a car to cover a distance
C.
Wind mill grinding wheat grain
D.
Rowing a boat in the lake
Ans:
Driving a car to cover a distance
Explanation :
The work done on any object goes into changing the kinetic energy of that object. Since the work done by the car engine is equal to the change in kinetic energy of the car we can say that kinetic energy is being used in performing work. The kinetic energy of an object is the energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.
[10] The spoon dropped by an astronaut in a satellite will –
A.
Fall to the floor
B.
Remain stationary
C.
Continue to follow the motion of the satellite
D.
Move tangentially away
Ans:
Continue to follow the motion of the satellite
Explanation :
An orbiting satellite is a projectile in the sense that the only force acting upon an orbiting satellite is the force of gravity. A satellite is acted upon by the force of gravity and this force does accelerate it towards the Earth. In the absence of gravity a satellite would move in a straight line path tangent to the Earth. In the absence of any forces whatsoever, an object in motion (such as a satellite) would continue in motion with the same speed and in the same direction.
[11] Stars appears to move from east to west because -
A.
all stars move from east to west
B.
the earth rotates from west to east
C.
the earth rotates from east to west
D.
the background of the stars moves from west to east
Ans:
the earth rotates from west to east
Explanation :
Earth’s spin (or rotation) on its axis. Earth rotates or spins toward the east, and that’s why the Sun, Moon, planets, and stars all rise in the east and make their way westward across the sky.
[12] Which of the following options correctly explains the term heat budget?
A.
It is a mode of transfer of heat through matter by molecular activity.
B.
It is the balance between incoming and outgoing radiation.
C.
It is the radiation from the earth in the form of long waves.
D.
It is the amount of heat which the surface of earth receives from the sun.
Ans:
It is the balance between incoming and outgoing radiation.
Explanation :
Incoming heat being absorbed by the Earth, and outgoing heat escaping the Earth in the form of radiation are both perfectly balanced. If they were not balanced, then Earth would be getting either progressively warmer or progressively cooler with each passing year. This balance between incoming and outgoing heat is known as Earth's heat budget.
[13] The purpose of choke in a fluorescent lamp is –
A.
to increase the current flow
B.
to decrease the current flow
C.
to decrease the resistance
D.
to decrease the voltage momentarily
Ans:
to decrease the current flow
Explanation :
The choke primarily serves to limit current flow to the correct level for the tube. It also can be used during startup to provide an inductive 'kick' forming a momentary higher-voltage pulse to start the lamp.
[14] To prevent damage from lightning, lightning conductors are used on tall structures. The lightning conductor –
A.
should be made of a good conductor but can be of any shape
B.
should be in the form of a vertical rod
C.
can be of any shape
D.
should be made of a good conductor like copper with sharp-pointed edges
Ans:
should be made of a good conductor like copper with sharp-pointed edges
Explanation :
A lightning conductor is made up of a sharp pointed metal (usually copper metal, as it is a very good conductor) connected directly to the ground. It is placed higher than the roof so that if lightning strikes, it strikes the conductor before it can reach the house. It should be pointed because when the negative charge is discharged by the cloud, it will first strike the pointed tip of the lightning conductor and quickly travel to the earth.
[15] Beta rays emitted by a radioactive material are –
A.
The electrons orbiting around the nucleus
B.
Charged particles emitted by nucleus
C.
Neutral particles
D.
Electromagnetic radiations
Ans:
Charged particles emitted by nucleus
Explanation :
A beta ray is a high-energy, high-speed electron (negatively charged) or positron (positively charged) emitted in the radioactive decay of an atomic nucleus, such as a potassium-40 nucleus, in the process of beta decay.
[16] What is the principle of a life Jacket'?
A.
It provides oxygen to a drowning person
B.
It increases the volume of the person to keep him afloat
C.
It decreases the volume of the person to keep him afloat
D.
The person can sit on it like a raft
Ans:
It increases the volume of the person to keep him afloat
Explanation :
The upward-pushing force that keeps things afloat is called buoyancy. For an object to float it must be able to equal its own weight by displacing enough water. A life jacket is mainly filled with gas which has a very low mass. As such when worn by a person, it acts to significantly increase their volume for only a very small increase in their mass.
[17] Steam at 100°C causes more severe burns than water at 100° C because –
A.
steam has no specific heat capacity
B.
steam has latent heat of vaporization
C.
water has no specific heat capacity
D.
water has latent heat of fusion
Ans:
steam has latent heat of vaporization
Explanation :
It is because steam releases its latent heat as it condenses, which is substantial. The heat of vaporization of steam is over 2000 J per gram. And when it releases that it's then 100 degree water, the same as boiling water.
[18] Ice cubes are added to a glass of pure water and a glass of pure alcohol. The ice would be –
A.
at a higher level in water
B.
at a higher level in alcohol
C.
at the same level in both
D.
floating in alcohol and sinking in water
Ans:
at a higher level in water
Explanation :
Density of water is approx 1 g/ml; Density of Ice is approx 0.93g/ml; and Density of 100% pure ethanol is 0.79g/ml. So the density of ice cubes is lesser than water, but higher than alcohol. So it will float in water, but sink in alcohol.
[19] Indicate the false statement about the resistance of a wire –
A.
it depends on material of wire
B.
it is directly proportional to the length of wire
C.
it is directly proportional to the area of cross-section of wire
D.
resistance of metallic wire increases with increase in temperature
Ans:
it is directly proportional to the area of cross-section of wire
Explanation :
The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it The SI unit of resistance is ohm.
[20] A metal ball and a rubber ball, both having the same mass, strike a wall normally with the same velocity. The rubber ball rebounds and the metal ball does not rebound. It can be concluded that –
A.
The rubber ball suffers greater change in momentum
B.
The metal ball suffers greater change in momentum
C.
Both suffer the same change in momentum
D.
The initial momentum of the rubber ball is greater than that of the metal ball
Ans:
The rubber ball suffers greater change in momentum
Explanation :
As per the question, the rubber ball rebounds while the metal ball does not. So if m and v be the mass and velocity respectively, the change in momentum of rubber ball = 2 mv (in magnitude) However, the change in momentum of the metal ball = mv The rubber ball suffers almost twice the change in momentum as experienced by the metal ball.
[21] In a conductor –
A.
there is no conduction band
B.
the forbidden energy gap is very wide
C.
the forbidden energy gap is very narrow
D.
the valence band and the conduction band overlap each other
Ans:
the valence band and the conduction band overlap each other
Explanation :
In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band. Conduction energy band
[22] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because –
A.
Mercury is a metal
B.
Density of mercury is greater than that of water
C.
Cohesion of mercury is greater than its adhesion with glass
D.
Cohesion of water is greater than its adhesion with glass
Ans:
Cohesion of mercury is greater than its adhesion with glass
Explanation :
When liquid is placed on a smooth surface like glass plate, the relative strengths of the cohesive and adhesive forces acting on that liquid determine the shape it will take (and whether or not it will wet the surface). If the adhesive forces between a liquid and a surface are stronger, they will pull the liquid down, causing it to wet the surface.
[23] The mass-energy relation is the outcome of –
A.
quantum theory
B.
general theory of relativity
C.
field theory of energy
D.
special theory of relativity
Ans:
special theory of relativity
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
It is because image formed by an convex mirror is always virtual, erect and smaller than the object.
[2] Railway tracks are banked on curves so that –
A.
Necessary centrifugal force may be obtained from the horizontal component of the weight of the train
B.
No frictional force may be produced between the tracks and the wheels of the train
C.
Necessary centripetal force may be obtained from the horizontal component of the weight of the train
D.
The train may not fall down inwards
Ans:
Necessary centripetal force may be obtained from the horizontal component of the weight of the train
Explanation :
Railway tracks are banked on curves so that necessary centripetal force may be obtained from the horizontal component of the weight of the train. It helps the train to stay on the track as it negotiates the curve. The raised track provides required centripetal force to enable it to move round the curve.
[3] What is the range of mercury thermometer?
A.
0 degree Celsius to 350 degree Celsius
B.
-10 degree Celsius to 350 degree Celsius
C.
-20 degree Celsius to 350 degree Celsius
D.
-30 degree Celsius to 350 degree Celsius
Ans:
-30 degree Celsius to 350 degree Celsius
Explanation :
[4] The width of depletion layer of a P-N junction –
A.
decreases with light doping
B.
increases with heavy doping
C.
is independent of applied voltage
D.
is increased under reverse bias
Ans:
is increased under reverse bias
Explanation :
The total width of the depletion region is a function of applied reverse-bias and impurity concentration. Forward bias decreases the depletion region width whilst reverse bias increases it.
[5] Ventilators are provided near the ceiling of the room because –
A.
the exhaled warmer air rises up and goes out
B.
these provide cross ventilation in the room
C.
these provide some sunlight in the room
D.
these do not look nice in the lower part
Ans:
the exhaled warmer air rises up and goes out
Explanation :
Ventilation is a room air distribution strategy where conditioned outdoor air is supplied at floor level and extracted above the occupied zone, usually at ceiling height. A typical displacement ventilation system, such as one in an office space, supplies conditioned cool air from an air handling unit (AHU) through a low induction diffuser. The cool air spreads through the floor of the space and then rises as the air warms due to heat exchange with heat sources in the space (e.g., occupants, computers, lights).
[6] What Is a neuron?
A.
Basic unit of energy
B.
Particle released during radioactivity
C.
The anti-particle of neutron
D.
Basle unit of nervous system
Ans:
Basle unit of nervous system
Explanation :
A neuron is a nerve cell that is the basic building block of the nervous system. Neurons are specialized to transmit information throughout the body. These highly specialized nerve cells are responsible for communicating information in both chemical and electrical forms.
[7] Which of the following is not caused by atmospheric refraction of light?
A.
Sun appearing red at sunset
B.
Twinkling of stars at night
C.
Sun appearing higher in the sky than it actually is
D.
Sun becoming visible two or three minutes before actual sunrise
Ans:
Sun appearing higher in the sky than it actually is
Explanation :
The twinkling of stars and variation in size of the Sun are due to atmospheric refraction of light. Besides, refraction is also responsible for the sun to look during sunset and suntise. It is also responsible for the sun becoming two or three minutes before actual sunrise. The sun appears higher or lower in the sky due to the changing position of the Earth relative to the Sun.
[8] Why the needle of iron swims on water surface when it is kept gently?
A.
It will remain under the water, when it will displace more water than its weight
B.
the density of needle is less than that of water
C.
due to surface tension
D.
due to its shape
Ans:
due to surface tension
Explanation :
According to Archimedes principle and we can note that the amount of water displaced by a needle is lesser than the amount of water moved out by the needle (that is displacement of the needle). So the needle initially stays on the surface of the water and then sinks into the water. Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force.
[9] In which of the following cases, kinetic energy is being used in performing work?
A.
Paddling the bicycle to cover a distance
B.
Driving a car to cover a distance
C.
Wind mill grinding wheat grain
D.
Rowing a boat in the lake
Ans:
Driving a car to cover a distance
Explanation :
The work done on any object goes into changing the kinetic energy of that object. Since the work done by the car engine is equal to the change in kinetic energy of the car we can say that kinetic energy is being used in performing work. The kinetic energy of an object is the energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.
[10] The spoon dropped by an astronaut in a satellite will –
A.
Fall to the floor
B.
Remain stationary
C.
Continue to follow the motion of the satellite
D.
Move tangentially away
Ans:
Continue to follow the motion of the satellite
Explanation :
An orbiting satellite is a projectile in the sense that the only force acting upon an orbiting satellite is the force of gravity. A satellite is acted upon by the force of gravity and this force does accelerate it towards the Earth. In the absence of gravity a satellite would move in a straight line path tangent to the Earth. In the absence of any forces whatsoever, an object in motion (such as a satellite) would continue in motion with the same speed and in the same direction.
[11] Stars appears to move from east to west because -
A.
all stars move from east to west
B.
the earth rotates from west to east
C.
the earth rotates from east to west
D.
the background of the stars moves from west to east
Ans:
the earth rotates from west to east
Explanation :
Earth’s spin (or rotation) on its axis. Earth rotates or spins toward the east, and that’s why the Sun, Moon, planets, and stars all rise in the east and make their way westward across the sky.
[12] Which of the following options correctly explains the term heat budget?
A.
It is a mode of transfer of heat through matter by molecular activity.
B.
It is the balance between incoming and outgoing radiation.
C.
It is the radiation from the earth in the form of long waves.
D.
It is the amount of heat which the surface of earth receives from the sun.
Ans:
It is the balance between incoming and outgoing radiation.
Explanation :
Incoming heat being absorbed by the Earth, and outgoing heat escaping the Earth in the form of radiation are both perfectly balanced. If they were not balanced, then Earth would be getting either progressively warmer or progressively cooler with each passing year. This balance between incoming and outgoing heat is known as Earth's heat budget.
[13] The purpose of choke in a fluorescent lamp is –
A.
to increase the current flow
B.
to decrease the current flow
C.
to decrease the resistance
D.
to decrease the voltage momentarily
Ans:
to decrease the current flow
Explanation :
The choke primarily serves to limit current flow to the correct level for the tube. It also can be used during startup to provide an inductive 'kick' forming a momentary higher-voltage pulse to start the lamp.
[14] To prevent damage from lightning, lightning conductors are used on tall structures. The lightning conductor –
A.
should be made of a good conductor but can be of any shape
B.
should be in the form of a vertical rod
C.
can be of any shape
D.
should be made of a good conductor like copper with sharp-pointed edges
Ans:
should be made of a good conductor like copper with sharp-pointed edges
Explanation :
A lightning conductor is made up of a sharp pointed metal (usually copper metal, as it is a very good conductor) connected directly to the ground. It is placed higher than the roof so that if lightning strikes, it strikes the conductor before it can reach the house. It should be pointed because when the negative charge is discharged by the cloud, it will first strike the pointed tip of the lightning conductor and quickly travel to the earth.
[15] Beta rays emitted by a radioactive material are –
A.
The electrons orbiting around the nucleus
B.
Charged particles emitted by nucleus
C.
Neutral particles
D.
Electromagnetic radiations
Ans:
Charged particles emitted by nucleus
Explanation :
A beta ray is a high-energy, high-speed electron (negatively charged) or positron (positively charged) emitted in the radioactive decay of an atomic nucleus, such as a potassium-40 nucleus, in the process of beta decay.
[16] What is the principle of a life Jacket'?
A.
It provides oxygen to a drowning person
B.
It increases the volume of the person to keep him afloat
C.
It decreases the volume of the person to keep him afloat
D.
The person can sit on it like a raft
Ans:
It increases the volume of the person to keep him afloat
Explanation :
The upward-pushing force that keeps things afloat is called buoyancy. For an object to float it must be able to equal its own weight by displacing enough water. A life jacket is mainly filled with gas which has a very low mass. As such when worn by a person, it acts to significantly increase their volume for only a very small increase in their mass.
[17] Steam at 100°C causes more severe burns than water at 100° C because –
A.
steam has no specific heat capacity
B.
steam has latent heat of vaporization
C.
water has no specific heat capacity
D.
water has latent heat of fusion
Ans:
steam has latent heat of vaporization
Explanation :
It is because steam releases its latent heat as it condenses, which is substantial. The heat of vaporization of steam is over 2000 J per gram. And when it releases that it's then 100 degree water, the same as boiling water.
[18] Ice cubes are added to a glass of pure water and a glass of pure alcohol. The ice would be –
A.
at a higher level in water
B.
at a higher level in alcohol
C.
at the same level in both
D.
floating in alcohol and sinking in water
Ans:
at a higher level in water
Explanation :
Density of water is approx 1 g/ml; Density of Ice is approx 0.93g/ml; and Density of 100% pure ethanol is 0.79g/ml. So the density of ice cubes is lesser than water, but higher than alcohol. So it will float in water, but sink in alcohol.
[19] Indicate the false statement about the resistance of a wire –
A.
it depends on material of wire
B.
it is directly proportional to the length of wire
C.
it is directly proportional to the area of cross-section of wire
D.
resistance of metallic wire increases with increase in temperature
Ans:
it is directly proportional to the area of cross-section of wire
Explanation :
The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it The SI unit of resistance is ohm.
[20] A metal ball and a rubber ball, both having the same mass, strike a wall normally with the same velocity. The rubber ball rebounds and the metal ball does not rebound. It can be concluded that –
A.
The rubber ball suffers greater change in momentum
B.
The metal ball suffers greater change in momentum
C.
Both suffer the same change in momentum
D.
The initial momentum of the rubber ball is greater than that of the metal ball
Ans:
The rubber ball suffers greater change in momentum
Explanation :
As per the question, the rubber ball rebounds while the metal ball does not. So if m and v be the mass and velocity respectively, the change in momentum of rubber ball = 2 mv (in magnitude) However, the change in momentum of the metal ball = mv The rubber ball suffers almost twice the change in momentum as experienced by the metal ball.
[21] In a conductor –
A.
there is no conduction band
B.
the forbidden energy gap is very wide
C.
the forbidden energy gap is very narrow
D.
the valence band and the conduction band overlap each other
Ans:
the valence band and the conduction band overlap each other
Explanation :
In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band. Conduction energy band
[22] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because –
A.
Mercury is a metal
B.
Density of mercury is greater than that of water
C.
Cohesion of mercury is greater than its adhesion with glass
D.
Cohesion of water is greater than its adhesion with glass
Ans:
Cohesion of mercury is greater than its adhesion with glass
Explanation :
When liquid is placed on a smooth surface like glass plate, the relative strengths of the cohesive and adhesive forces acting on that liquid determine the shape it will take (and whether or not it will wet the surface). If the adhesive forces between a liquid and a surface are stronger, they will pull the liquid down, causing it to wet the surface.
[23] The mass-energy relation is the outcome of –
A.
quantum theory
B.
general theory of relativity
C.
field theory of energy
D.
special theory of relativity
Ans:
special theory of relativity
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
[4] The width of depletion layer of a P-N junction –
A.
decreases with light doping
B.
increases with heavy doping
C.
is independent of applied voltage
D.
is increased under reverse bias
Ans:
is increased under reverse bias
Explanation :
The total width of the depletion region is a function of applied reverse-bias and impurity concentration. Forward bias decreases the depletion region width whilst reverse bias increases it.
[5] Ventilators are provided near the ceiling of the room because –
A.
the exhaled warmer air rises up and goes out
B.
these provide cross ventilation in the room
C.
these provide some sunlight in the room
D.
these do not look nice in the lower part
Ans:
the exhaled warmer air rises up and goes out
Explanation :
Ventilation is a room air distribution strategy where conditioned outdoor air is supplied at floor level and extracted above the occupied zone, usually at ceiling height. A typical displacement ventilation system, such as one in an office space, supplies conditioned cool air from an air handling unit (AHU) through a low induction diffuser. The cool air spreads through the floor of the space and then rises as the air warms due to heat exchange with heat sources in the space (e.g., occupants, computers, lights).
[6] What Is a neuron?
A.
Basic unit of energy
B.
Particle released during radioactivity
C.
The anti-particle of neutron
D.
Basle unit of nervous system
Ans:
Basle unit of nervous system
Explanation :
A neuron is a nerve cell that is the basic building block of the nervous system. Neurons are specialized to transmit information throughout the body. These highly specialized nerve cells are responsible for communicating information in both chemical and electrical forms.
[7] Which of the following is not caused by atmospheric refraction of light?
A.
Sun appearing red at sunset
B.
Twinkling of stars at night
C.
Sun appearing higher in the sky than it actually is
D.
Sun becoming visible two or three minutes before actual sunrise
Ans:
Sun appearing higher in the sky than it actually is
Explanation :
The twinkling of stars and variation in size of the Sun are due to atmospheric refraction of light. Besides, refraction is also responsible for the sun to look during sunset and suntise. It is also responsible for the sun becoming two or three minutes before actual sunrise. The sun appears higher or lower in the sky due to the changing position of the Earth relative to the Sun.
[8] Why the needle of iron swims on water surface when it is kept gently?
A.
It will remain under the water, when it will displace more water than its weight
B.
the density of needle is less than that of water
C.
due to surface tension
D.
due to its shape
Ans:
due to surface tension
Explanation :
According to Archimedes principle and we can note that the amount of water displaced by a needle is lesser than the amount of water moved out by the needle (that is displacement of the needle). So the needle initially stays on the surface of the water and then sinks into the water. Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force.
[9] In which of the following cases, kinetic energy is being used in performing work?
A.
Paddling the bicycle to cover a distance
B.
Driving a car to cover a distance
C.
Wind mill grinding wheat grain
D.
Rowing a boat in the lake
Ans:
Driving a car to cover a distance
Explanation :
The work done on any object goes into changing the kinetic energy of that object. Since the work done by the car engine is equal to the change in kinetic energy of the car we can say that kinetic energy is being used in performing work. The kinetic energy of an object is the energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.
[10] The spoon dropped by an astronaut in a satellite will –
A.
Fall to the floor
B.
Remain stationary
C.
Continue to follow the motion of the satellite
D.
Move tangentially away
Ans:
Continue to follow the motion of the satellite
Explanation :
An orbiting satellite is a projectile in the sense that the only force acting upon an orbiting satellite is the force of gravity. A satellite is acted upon by the force of gravity and this force does accelerate it towards the Earth. In the absence of gravity a satellite would move in a straight line path tangent to the Earth. In the absence of any forces whatsoever, an object in motion (such as a satellite) would continue in motion with the same speed and in the same direction.
[11] Stars appears to move from east to west because -
A.
all stars move from east to west
B.
the earth rotates from west to east
C.
the earth rotates from east to west
D.
the background of the stars moves from west to east
Ans:
the earth rotates from west to east
Explanation :
Earth’s spin (or rotation) on its axis. Earth rotates or spins toward the east, and that’s why the Sun, Moon, planets, and stars all rise in the east and make their way westward across the sky.
[12] Which of the following options correctly explains the term heat budget?
A.
It is a mode of transfer of heat through matter by molecular activity.
B.
It is the balance between incoming and outgoing radiation.
C.
It is the radiation from the earth in the form of long waves.
D.
It is the amount of heat which the surface of earth receives from the sun.
Ans:
It is the balance between incoming and outgoing radiation.
Explanation :
Incoming heat being absorbed by the Earth, and outgoing heat escaping the Earth in the form of radiation are both perfectly balanced. If they were not balanced, then Earth would be getting either progressively warmer or progressively cooler with each passing year. This balance between incoming and outgoing heat is known as Earth's heat budget.
[13] The purpose of choke in a fluorescent lamp is –
A.
to increase the current flow
B.
to decrease the current flow
C.
to decrease the resistance
D.
to decrease the voltage momentarily
Ans:
to decrease the current flow
Explanation :
The choke primarily serves to limit current flow to the correct level for the tube. It also can be used during startup to provide an inductive 'kick' forming a momentary higher-voltage pulse to start the lamp.
[14] To prevent damage from lightning, lightning conductors are used on tall structures. The lightning conductor –
A.
should be made of a good conductor but can be of any shape
B.
should be in the form of a vertical rod
C.
can be of any shape
D.
should be made of a good conductor like copper with sharp-pointed edges
Ans:
should be made of a good conductor like copper with sharp-pointed edges
Explanation :
A lightning conductor is made up of a sharp pointed metal (usually copper metal, as it is a very good conductor) connected directly to the ground. It is placed higher than the roof so that if lightning strikes, it strikes the conductor before it can reach the house. It should be pointed because when the negative charge is discharged by the cloud, it will first strike the pointed tip of the lightning conductor and quickly travel to the earth.
[15] Beta rays emitted by a radioactive material are –
A.
The electrons orbiting around the nucleus
B.
Charged particles emitted by nucleus
C.
Neutral particles
D.
Electromagnetic radiations
Ans:
Charged particles emitted by nucleus
Explanation :
A beta ray is a high-energy, high-speed electron (negatively charged) or positron (positively charged) emitted in the radioactive decay of an atomic nucleus, such as a potassium-40 nucleus, in the process of beta decay.
[16] What is the principle of a life Jacket'?
A.
It provides oxygen to a drowning person
B.
It increases the volume of the person to keep him afloat
C.
It decreases the volume of the person to keep him afloat
D.
The person can sit on it like a raft
Ans:
It increases the volume of the person to keep him afloat
Explanation :
The upward-pushing force that keeps things afloat is called buoyancy. For an object to float it must be able to equal its own weight by displacing enough water. A life jacket is mainly filled with gas which has a very low mass. As such when worn by a person, it acts to significantly increase their volume for only a very small increase in their mass.
[17] Steam at 100°C causes more severe burns than water at 100° C because –
A.
steam has no specific heat capacity
B.
steam has latent heat of vaporization
C.
water has no specific heat capacity
D.
water has latent heat of fusion
Ans:
steam has latent heat of vaporization
Explanation :
It is because steam releases its latent heat as it condenses, which is substantial. The heat of vaporization of steam is over 2000 J per gram. And when it releases that it's then 100 degree water, the same as boiling water.
[18] Ice cubes are added to a glass of pure water and a glass of pure alcohol. The ice would be –
A.
at a higher level in water
B.
at a higher level in alcohol
C.
at the same level in both
D.
floating in alcohol and sinking in water
Ans:
at a higher level in water
Explanation :
Density of water is approx 1 g/ml; Density of Ice is approx 0.93g/ml; and Density of 100% pure ethanol is 0.79g/ml. So the density of ice cubes is lesser than water, but higher than alcohol. So it will float in water, but sink in alcohol.
[19] Indicate the false statement about the resistance of a wire –
A.
it depends on material of wire
B.
it is directly proportional to the length of wire
C.
it is directly proportional to the area of cross-section of wire
D.
resistance of metallic wire increases with increase in temperature
Ans:
it is directly proportional to the area of cross-section of wire
Explanation :
The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it The SI unit of resistance is ohm.
[20] A metal ball and a rubber ball, both having the same mass, strike a wall normally with the same velocity. The rubber ball rebounds and the metal ball does not rebound. It can be concluded that –
A.
The rubber ball suffers greater change in momentum
B.
The metal ball suffers greater change in momentum
C.
Both suffer the same change in momentum
D.
The initial momentum of the rubber ball is greater than that of the metal ball
Ans:
The rubber ball suffers greater change in momentum
Explanation :
As per the question, the rubber ball rebounds while the metal ball does not. So if m and v be the mass and velocity respectively, the change in momentum of rubber ball = 2 mv (in magnitude) However, the change in momentum of the metal ball = mv The rubber ball suffers almost twice the change in momentum as experienced by the metal ball.
[21] In a conductor –
A.
there is no conduction band
B.
the forbidden energy gap is very wide
C.
the forbidden energy gap is very narrow
D.
the valence band and the conduction band overlap each other
Ans:
the valence band and the conduction band overlap each other
Explanation :
In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band. Conduction energy band
[22] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because –
A.
Mercury is a metal
B.
Density of mercury is greater than that of water
C.
Cohesion of mercury is greater than its adhesion with glass
D.
Cohesion of water is greater than its adhesion with glass
Ans:
Cohesion of mercury is greater than its adhesion with glass
Explanation :
When liquid is placed on a smooth surface like glass plate, the relative strengths of the cohesive and adhesive forces acting on that liquid determine the shape it will take (and whether or not it will wet the surface). If the adhesive forces between a liquid and a surface are stronger, they will pull the liquid down, causing it to wet the surface.
[23] The mass-energy relation is the outcome of –
A.
quantum theory
B.
general theory of relativity
C.
field theory of energy
D.
special theory of relativity
Ans:
special theory of relativity
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
Ventilation is a room air distribution strategy where conditioned outdoor air is supplied at floor level and extracted above the occupied zone, usually at ceiling height. A typical displacement ventilation system, such as one in an office space, supplies conditioned cool air from an air handling unit (AHU) through a low induction diffuser. The cool air spreads through the floor of the space and then rises as the air warms due to heat exchange with heat sources in the space (e.g., occupants, computers, lights).
[6] What Is a neuron?
A.
Basic unit of energy
B.
Particle released during radioactivity
C.
The anti-particle of neutron
D.
Basle unit of nervous system
Ans:
Basle unit of nervous system
Explanation :
A neuron is a nerve cell that is the basic building block of the nervous system. Neurons are specialized to transmit information throughout the body. These highly specialized nerve cells are responsible for communicating information in both chemical and electrical forms.
[7] Which of the following is not caused by atmospheric refraction of light?
A.
Sun appearing red at sunset
B.
Twinkling of stars at night
C.
Sun appearing higher in the sky than it actually is
D.
Sun becoming visible two or three minutes before actual sunrise
Ans:
Sun appearing higher in the sky than it actually is
Explanation :
The twinkling of stars and variation in size of the Sun are due to atmospheric refraction of light. Besides, refraction is also responsible for the sun to look during sunset and suntise. It is also responsible for the sun becoming two or three minutes before actual sunrise. The sun appears higher or lower in the sky due to the changing position of the Earth relative to the Sun.
[8] Why the needle of iron swims on water surface when it is kept gently?
A.
It will remain under the water, when it will displace more water than its weight
B.
the density of needle is less than that of water
C.
due to surface tension
D.
due to its shape
Ans:
due to surface tension
Explanation :
According to Archimedes principle and we can note that the amount of water displaced by a needle is lesser than the amount of water moved out by the needle (that is displacement of the needle). So the needle initially stays on the surface of the water and then sinks into the water. Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force.
[9] In which of the following cases, kinetic energy is being used in performing work?
A.
Paddling the bicycle to cover a distance
B.
Driving a car to cover a distance
C.
Wind mill grinding wheat grain
D.
Rowing a boat in the lake
Ans:
Driving a car to cover a distance
Explanation :
The work done on any object goes into changing the kinetic energy of that object. Since the work done by the car engine is equal to the change in kinetic energy of the car we can say that kinetic energy is being used in performing work. The kinetic energy of an object is the energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.
[10] The spoon dropped by an astronaut in a satellite will –
A.
Fall to the floor
B.
Remain stationary
C.
Continue to follow the motion of the satellite
D.
Move tangentially away
Ans:
Continue to follow the motion of the satellite
Explanation :
An orbiting satellite is a projectile in the sense that the only force acting upon an orbiting satellite is the force of gravity. A satellite is acted upon by the force of gravity and this force does accelerate it towards the Earth. In the absence of gravity a satellite would move in a straight line path tangent to the Earth. In the absence of any forces whatsoever, an object in motion (such as a satellite) would continue in motion with the same speed and in the same direction.
[11] Stars appears to move from east to west because -
A.
all stars move from east to west
B.
the earth rotates from west to east
C.
the earth rotates from east to west
D.
the background of the stars moves from west to east
Ans:
the earth rotates from west to east
Explanation :
Earth’s spin (or rotation) on its axis. Earth rotates or spins toward the east, and that’s why the Sun, Moon, planets, and stars all rise in the east and make their way westward across the sky.
[12] Which of the following options correctly explains the term heat budget?
A.
It is a mode of transfer of heat through matter by molecular activity.
B.
It is the balance between incoming and outgoing radiation.
C.
It is the radiation from the earth in the form of long waves.
D.
It is the amount of heat which the surface of earth receives from the sun.
Ans:
It is the balance between incoming and outgoing radiation.
Explanation :
Incoming heat being absorbed by the Earth, and outgoing heat escaping the Earth in the form of radiation are both perfectly balanced. If they were not balanced, then Earth would be getting either progressively warmer or progressively cooler with each passing year. This balance between incoming and outgoing heat is known as Earth's heat budget.
[13] The purpose of choke in a fluorescent lamp is –
A.
to increase the current flow
B.
to decrease the current flow
C.
to decrease the resistance
D.
to decrease the voltage momentarily
Ans:
to decrease the current flow
Explanation :
The choke primarily serves to limit current flow to the correct level for the tube. It also can be used during startup to provide an inductive 'kick' forming a momentary higher-voltage pulse to start the lamp.
[14] To prevent damage from lightning, lightning conductors are used on tall structures. The lightning conductor –
A.
should be made of a good conductor but can be of any shape
B.
should be in the form of a vertical rod
C.
can be of any shape
D.
should be made of a good conductor like copper with sharp-pointed edges
Ans:
should be made of a good conductor like copper with sharp-pointed edges
Explanation :
A lightning conductor is made up of a sharp pointed metal (usually copper metal, as it is a very good conductor) connected directly to the ground. It is placed higher than the roof so that if lightning strikes, it strikes the conductor before it can reach the house. It should be pointed because when the negative charge is discharged by the cloud, it will first strike the pointed tip of the lightning conductor and quickly travel to the earth.
[15] Beta rays emitted by a radioactive material are –
A.
The electrons orbiting around the nucleus
B.
Charged particles emitted by nucleus
C.
Neutral particles
D.
Electromagnetic radiations
Ans:
Charged particles emitted by nucleus
Explanation :
A beta ray is a high-energy, high-speed electron (negatively charged) or positron (positively charged) emitted in the radioactive decay of an atomic nucleus, such as a potassium-40 nucleus, in the process of beta decay.
[16] What is the principle of a life Jacket'?
A.
It provides oxygen to a drowning person
B.
It increases the volume of the person to keep him afloat
C.
It decreases the volume of the person to keep him afloat
D.
The person can sit on it like a raft
Ans:
It increases the volume of the person to keep him afloat
Explanation :
The upward-pushing force that keeps things afloat is called buoyancy. For an object to float it must be able to equal its own weight by displacing enough water. A life jacket is mainly filled with gas which has a very low mass. As such when worn by a person, it acts to significantly increase their volume for only a very small increase in their mass.
[17] Steam at 100°C causes more severe burns than water at 100° C because –
A.
steam has no specific heat capacity
B.
steam has latent heat of vaporization
C.
water has no specific heat capacity
D.
water has latent heat of fusion
Ans:
steam has latent heat of vaporization
Explanation :
It is because steam releases its latent heat as it condenses, which is substantial. The heat of vaporization of steam is over 2000 J per gram. And when it releases that it's then 100 degree water, the same as boiling water.
[18] Ice cubes are added to a glass of pure water and a glass of pure alcohol. The ice would be –
A.
at a higher level in water
B.
at a higher level in alcohol
C.
at the same level in both
D.
floating in alcohol and sinking in water
Ans:
at a higher level in water
Explanation :
Density of water is approx 1 g/ml; Density of Ice is approx 0.93g/ml; and Density of 100% pure ethanol is 0.79g/ml. So the density of ice cubes is lesser than water, but higher than alcohol. So it will float in water, but sink in alcohol.
[19] Indicate the false statement about the resistance of a wire –
A.
it depends on material of wire
B.
it is directly proportional to the length of wire
C.
it is directly proportional to the area of cross-section of wire
D.
resistance of metallic wire increases with increase in temperature
Ans:
it is directly proportional to the area of cross-section of wire
Explanation :
The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it The SI unit of resistance is ohm.
[20] A metal ball and a rubber ball, both having the same mass, strike a wall normally with the same velocity. The rubber ball rebounds and the metal ball does not rebound. It can be concluded that –
A.
The rubber ball suffers greater change in momentum
B.
The metal ball suffers greater change in momentum
C.
Both suffer the same change in momentum
D.
The initial momentum of the rubber ball is greater than that of the metal ball
Ans:
The rubber ball suffers greater change in momentum
Explanation :
As per the question, the rubber ball rebounds while the metal ball does not. So if m and v be the mass and velocity respectively, the change in momentum of rubber ball = 2 mv (in magnitude) However, the change in momentum of the metal ball = mv The rubber ball suffers almost twice the change in momentum as experienced by the metal ball.
[21] In a conductor –
A.
there is no conduction band
B.
the forbidden energy gap is very wide
C.
the forbidden energy gap is very narrow
D.
the valence band and the conduction band overlap each other
Ans:
the valence band and the conduction band overlap each other
Explanation :
In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band. Conduction energy band
[22] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because –
A.
Mercury is a metal
B.
Density of mercury is greater than that of water
C.
Cohesion of mercury is greater than its adhesion with glass
D.
Cohesion of water is greater than its adhesion with glass
Ans:
Cohesion of mercury is greater than its adhesion with glass
Explanation :
When liquid is placed on a smooth surface like glass plate, the relative strengths of the cohesive and adhesive forces acting on that liquid determine the shape it will take (and whether or not it will wet the surface). If the adhesive forces between a liquid and a surface are stronger, they will pull the liquid down, causing it to wet the surface.
[23] The mass-energy relation is the outcome of –
A.
quantum theory
B.
general theory of relativity
C.
field theory of energy
D.
special theory of relativity
Ans:
special theory of relativity
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
The twinkling of stars and variation in size of the Sun are due to atmospheric refraction of light. Besides, refraction is also responsible for the sun to look during sunset and suntise. It is also responsible for the sun becoming two or three minutes before actual sunrise. The sun appears higher or lower in the sky due to the changing position of the Earth relative to the Sun.
[8] Why the needle of iron swims on water surface when it is kept gently?
A.
It will remain under the water, when it will displace more water than its weight
B.
the density of needle is less than that of water
C.
due to surface tension
D.
due to its shape
Ans:
due to surface tension
Explanation :
According to Archimedes principle and we can note that the amount of water displaced by a needle is lesser than the amount of water moved out by the needle (that is displacement of the needle). So the needle initially stays on the surface of the water and then sinks into the water. Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force.
[9] In which of the following cases, kinetic energy is being used in performing work?
A.
Paddling the bicycle to cover a distance
B.
Driving a car to cover a distance
C.
Wind mill grinding wheat grain
D.
Rowing a boat in the lake
Ans:
Driving a car to cover a distance
Explanation :
The work done on any object goes into changing the kinetic energy of that object. Since the work done by the car engine is equal to the change in kinetic energy of the car we can say that kinetic energy is being used in performing work. The kinetic energy of an object is the energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.
[10] The spoon dropped by an astronaut in a satellite will –
A.
Fall to the floor
B.
Remain stationary
C.
Continue to follow the motion of the satellite
D.
Move tangentially away
Ans:
Continue to follow the motion of the satellite
Explanation :
An orbiting satellite is a projectile in the sense that the only force acting upon an orbiting satellite is the force of gravity. A satellite is acted upon by the force of gravity and this force does accelerate it towards the Earth. In the absence of gravity a satellite would move in a straight line path tangent to the Earth. In the absence of any forces whatsoever, an object in motion (such as a satellite) would continue in motion with the same speed and in the same direction.
[11] Stars appears to move from east to west because -
A.
all stars move from east to west
B.
the earth rotates from west to east
C.
the earth rotates from east to west
D.
the background of the stars moves from west to east
Ans:
the earth rotates from west to east
Explanation :
Earth’s spin (or rotation) on its axis. Earth rotates or spins toward the east, and that’s why the Sun, Moon, planets, and stars all rise in the east and make their way westward across the sky.
[12] Which of the following options correctly explains the term heat budget?
A.
It is a mode of transfer of heat through matter by molecular activity.
B.
It is the balance between incoming and outgoing radiation.
C.
It is the radiation from the earth in the form of long waves.
D.
It is the amount of heat which the surface of earth receives from the sun.
Ans:
It is the balance between incoming and outgoing radiation.
Explanation :
Incoming heat being absorbed by the Earth, and outgoing heat escaping the Earth in the form of radiation are both perfectly balanced. If they were not balanced, then Earth would be getting either progressively warmer or progressively cooler with each passing year. This balance between incoming and outgoing heat is known as Earth's heat budget.
[13] The purpose of choke in a fluorescent lamp is –
A.
to increase the current flow
B.
to decrease the current flow
C.
to decrease the resistance
D.
to decrease the voltage momentarily
Ans:
to decrease the current flow
Explanation :
The choke primarily serves to limit current flow to the correct level for the tube. It also can be used during startup to provide an inductive 'kick' forming a momentary higher-voltage pulse to start the lamp.
[14] To prevent damage from lightning, lightning conductors are used on tall structures. The lightning conductor –
A.
should be made of a good conductor but can be of any shape
B.
should be in the form of a vertical rod
C.
can be of any shape
D.
should be made of a good conductor like copper with sharp-pointed edges
Ans:
should be made of a good conductor like copper with sharp-pointed edges
Explanation :
A lightning conductor is made up of a sharp pointed metal (usually copper metal, as it is a very good conductor) connected directly to the ground. It is placed higher than the roof so that if lightning strikes, it strikes the conductor before it can reach the house. It should be pointed because when the negative charge is discharged by the cloud, it will first strike the pointed tip of the lightning conductor and quickly travel to the earth.
[15] Beta rays emitted by a radioactive material are –
A.
The electrons orbiting around the nucleus
B.
Charged particles emitted by nucleus
C.
Neutral particles
D.
Electromagnetic radiations
Ans:
Charged particles emitted by nucleus
Explanation :
A beta ray is a high-energy, high-speed electron (negatively charged) or positron (positively charged) emitted in the radioactive decay of an atomic nucleus, such as a potassium-40 nucleus, in the process of beta decay.
[16] What is the principle of a life Jacket'?
A.
It provides oxygen to a drowning person
B.
It increases the volume of the person to keep him afloat
C.
It decreases the volume of the person to keep him afloat
D.
The person can sit on it like a raft
Ans:
It increases the volume of the person to keep him afloat
Explanation :
The upward-pushing force that keeps things afloat is called buoyancy. For an object to float it must be able to equal its own weight by displacing enough water. A life jacket is mainly filled with gas which has a very low mass. As such when worn by a person, it acts to significantly increase their volume for only a very small increase in their mass.
[17] Steam at 100°C causes more severe burns than water at 100° C because –
A.
steam has no specific heat capacity
B.
steam has latent heat of vaporization
C.
water has no specific heat capacity
D.
water has latent heat of fusion
Ans:
steam has latent heat of vaporization
Explanation :
It is because steam releases its latent heat as it condenses, which is substantial. The heat of vaporization of steam is over 2000 J per gram. And when it releases that it's then 100 degree water, the same as boiling water.
[18] Ice cubes are added to a glass of pure water and a glass of pure alcohol. The ice would be –
A.
at a higher level in water
B.
at a higher level in alcohol
C.
at the same level in both
D.
floating in alcohol and sinking in water
Ans:
at a higher level in water
Explanation :
Density of water is approx 1 g/ml; Density of Ice is approx 0.93g/ml; and Density of 100% pure ethanol is 0.79g/ml. So the density of ice cubes is lesser than water, but higher than alcohol. So it will float in water, but sink in alcohol.
[19] Indicate the false statement about the resistance of a wire –
A.
it depends on material of wire
B.
it is directly proportional to the length of wire
C.
it is directly proportional to the area of cross-section of wire
D.
resistance of metallic wire increases with increase in temperature
Ans:
it is directly proportional to the area of cross-section of wire
Explanation :
The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it The SI unit of resistance is ohm.
[20] A metal ball and a rubber ball, both having the same mass, strike a wall normally with the same velocity. The rubber ball rebounds and the metal ball does not rebound. It can be concluded that –
A.
The rubber ball suffers greater change in momentum
B.
The metal ball suffers greater change in momentum
C.
Both suffer the same change in momentum
D.
The initial momentum of the rubber ball is greater than that of the metal ball
Ans:
The rubber ball suffers greater change in momentum
Explanation :
As per the question, the rubber ball rebounds while the metal ball does not. So if m and v be the mass and velocity respectively, the change in momentum of rubber ball = 2 mv (in magnitude) However, the change in momentum of the metal ball = mv The rubber ball suffers almost twice the change in momentum as experienced by the metal ball.
[21] In a conductor –
A.
there is no conduction band
B.
the forbidden energy gap is very wide
C.
the forbidden energy gap is very narrow
D.
the valence band and the conduction band overlap each other
Ans:
the valence band and the conduction band overlap each other
Explanation :
In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band. Conduction energy band
[22] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because –
A.
Mercury is a metal
B.
Density of mercury is greater than that of water
C.
Cohesion of mercury is greater than its adhesion with glass
D.
Cohesion of water is greater than its adhesion with glass
Ans:
Cohesion of mercury is greater than its adhesion with glass
Explanation :
When liquid is placed on a smooth surface like glass plate, the relative strengths of the cohesive and adhesive forces acting on that liquid determine the shape it will take (and whether or not it will wet the surface). If the adhesive forces between a liquid and a surface are stronger, they will pull the liquid down, causing it to wet the surface.
[23] The mass-energy relation is the outcome of –
A.
quantum theory
B.
general theory of relativity
C.
field theory of energy
D.
special theory of relativity
Ans:
special theory of relativity
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
The work done on any object goes into changing the kinetic energy of that object. Since the work done by the car engine is equal to the change in kinetic energy of the car we can say that kinetic energy is being used in performing work. The kinetic energy of an object is the energy which it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.
[10] The spoon dropped by an astronaut in a satellite will –
A.
Fall to the floor
B.
Remain stationary
C.
Continue to follow the motion of the satellite
D.
Move tangentially away
Ans:
Continue to follow the motion of the satellite
Explanation :
An orbiting satellite is a projectile in the sense that the only force acting upon an orbiting satellite is the force of gravity. A satellite is acted upon by the force of gravity and this force does accelerate it towards the Earth. In the absence of gravity a satellite would move in a straight line path tangent to the Earth. In the absence of any forces whatsoever, an object in motion (such as a satellite) would continue in motion with the same speed and in the same direction.
[11] Stars appears to move from east to west because -
A.
all stars move from east to west
B.
the earth rotates from west to east
C.
the earth rotates from east to west
D.
the background of the stars moves from west to east
Ans:
the earth rotates from west to east
Explanation :
Earth’s spin (or rotation) on its axis. Earth rotates or spins toward the east, and that’s why the Sun, Moon, planets, and stars all rise in the east and make their way westward across the sky.
[12] Which of the following options correctly explains the term heat budget?
A.
It is a mode of transfer of heat through matter by molecular activity.
B.
It is the balance between incoming and outgoing radiation.
C.
It is the radiation from the earth in the form of long waves.
D.
It is the amount of heat which the surface of earth receives from the sun.
Ans:
It is the balance between incoming and outgoing radiation.
Explanation :
Incoming heat being absorbed by the Earth, and outgoing heat escaping the Earth in the form of radiation are both perfectly balanced. If they were not balanced, then Earth would be getting either progressively warmer or progressively cooler with each passing year. This balance between incoming and outgoing heat is known as Earth's heat budget.
[13] The purpose of choke in a fluorescent lamp is –
A.
to increase the current flow
B.
to decrease the current flow
C.
to decrease the resistance
D.
to decrease the voltage momentarily
Ans:
to decrease the current flow
Explanation :
The choke primarily serves to limit current flow to the correct level for the tube. It also can be used during startup to provide an inductive 'kick' forming a momentary higher-voltage pulse to start the lamp.
[14] To prevent damage from lightning, lightning conductors are used on tall structures. The lightning conductor –
A.
should be made of a good conductor but can be of any shape
B.
should be in the form of a vertical rod
C.
can be of any shape
D.
should be made of a good conductor like copper with sharp-pointed edges
Ans:
should be made of a good conductor like copper with sharp-pointed edges
Explanation :
A lightning conductor is made up of a sharp pointed metal (usually copper metal, as it is a very good conductor) connected directly to the ground. It is placed higher than the roof so that if lightning strikes, it strikes the conductor before it can reach the house. It should be pointed because when the negative charge is discharged by the cloud, it will first strike the pointed tip of the lightning conductor and quickly travel to the earth.
[15] Beta rays emitted by a radioactive material are –
A.
The electrons orbiting around the nucleus
B.
Charged particles emitted by nucleus
C.
Neutral particles
D.
Electromagnetic radiations
Ans:
Charged particles emitted by nucleus
Explanation :
A beta ray is a high-energy, high-speed electron (negatively charged) or positron (positively charged) emitted in the radioactive decay of an atomic nucleus, such as a potassium-40 nucleus, in the process of beta decay.
[16] What is the principle of a life Jacket'?
A.
It provides oxygen to a drowning person
B.
It increases the volume of the person to keep him afloat
C.
It decreases the volume of the person to keep him afloat
D.
The person can sit on it like a raft
Ans:
It increases the volume of the person to keep him afloat
Explanation :
The upward-pushing force that keeps things afloat is called buoyancy. For an object to float it must be able to equal its own weight by displacing enough water. A life jacket is mainly filled with gas which has a very low mass. As such when worn by a person, it acts to significantly increase their volume for only a very small increase in their mass.
[17] Steam at 100°C causes more severe burns than water at 100° C because –
A.
steam has no specific heat capacity
B.
steam has latent heat of vaporization
C.
water has no specific heat capacity
D.
water has latent heat of fusion
Ans:
steam has latent heat of vaporization
Explanation :
It is because steam releases its latent heat as it condenses, which is substantial. The heat of vaporization of steam is over 2000 J per gram. And when it releases that it's then 100 degree water, the same as boiling water.
[18] Ice cubes are added to a glass of pure water and a glass of pure alcohol. The ice would be –
A.
at a higher level in water
B.
at a higher level in alcohol
C.
at the same level in both
D.
floating in alcohol and sinking in water
Ans:
at a higher level in water
Explanation :
Density of water is approx 1 g/ml; Density of Ice is approx 0.93g/ml; and Density of 100% pure ethanol is 0.79g/ml. So the density of ice cubes is lesser than water, but higher than alcohol. So it will float in water, but sink in alcohol.
[19] Indicate the false statement about the resistance of a wire –
A.
it depends on material of wire
B.
it is directly proportional to the length of wire
C.
it is directly proportional to the area of cross-section of wire
D.
resistance of metallic wire increases with increase in temperature
Ans:
it is directly proportional to the area of cross-section of wire
Explanation :
The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it The SI unit of resistance is ohm.
[20] A metal ball and a rubber ball, both having the same mass, strike a wall normally with the same velocity. The rubber ball rebounds and the metal ball does not rebound. It can be concluded that –
A.
The rubber ball suffers greater change in momentum
B.
The metal ball suffers greater change in momentum
C.
Both suffer the same change in momentum
D.
The initial momentum of the rubber ball is greater than that of the metal ball
Ans:
The rubber ball suffers greater change in momentum
Explanation :
As per the question, the rubber ball rebounds while the metal ball does not. So if m and v be the mass and velocity respectively, the change in momentum of rubber ball = 2 mv (in magnitude) However, the change in momentum of the metal ball = mv The rubber ball suffers almost twice the change in momentum as experienced by the metal ball.
[21] In a conductor –
A.
there is no conduction band
B.
the forbidden energy gap is very wide
C.
the forbidden energy gap is very narrow
D.
the valence band and the conduction band overlap each other
Ans:
the valence band and the conduction band overlap each other
Explanation :
In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band. Conduction energy band
[22] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because –
A.
Mercury is a metal
B.
Density of mercury is greater than that of water
C.
Cohesion of mercury is greater than its adhesion with glass
D.
Cohesion of water is greater than its adhesion with glass
Ans:
Cohesion of mercury is greater than its adhesion with glass
Explanation :
When liquid is placed on a smooth surface like glass plate, the relative strengths of the cohesive and adhesive forces acting on that liquid determine the shape it will take (and whether or not it will wet the surface). If the adhesive forces between a liquid and a surface are stronger, they will pull the liquid down, causing it to wet the surface.
[23] The mass-energy relation is the outcome of –
A.
quantum theory
B.
general theory of relativity
C.
field theory of energy
D.
special theory of relativity
Ans:
special theory of relativity
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
Earth’s spin (or rotation) on its axis. Earth rotates or spins toward the east, and that’s why the Sun, Moon, planets, and stars all rise in the east and make their way westward across the sky.
[12] Which of the following options correctly explains the term heat budget?
A.
It is a mode of transfer of heat through matter by molecular activity.
B.
It is the balance between incoming and outgoing radiation.
C.
It is the radiation from the earth in the form of long waves.
D.
It is the amount of heat which the surface of earth receives from the sun.
Ans:
It is the balance between incoming and outgoing radiation.
Explanation :
Incoming heat being absorbed by the Earth, and outgoing heat escaping the Earth in the form of radiation are both perfectly balanced. If they were not balanced, then Earth would be getting either progressively warmer or progressively cooler with each passing year. This balance between incoming and outgoing heat is known as Earth's heat budget.
[13] The purpose of choke in a fluorescent lamp is –
A.
to increase the current flow
B.
to decrease the current flow
C.
to decrease the resistance
D.
to decrease the voltage momentarily
Ans:
to decrease the current flow
Explanation :
The choke primarily serves to limit current flow to the correct level for the tube. It also can be used during startup to provide an inductive 'kick' forming a momentary higher-voltage pulse to start the lamp.
[14] To prevent damage from lightning, lightning conductors are used on tall structures. The lightning conductor –
A.
should be made of a good conductor but can be of any shape
B.
should be in the form of a vertical rod
C.
can be of any shape
D.
should be made of a good conductor like copper with sharp-pointed edges
Ans:
should be made of a good conductor like copper with sharp-pointed edges
Explanation :
A lightning conductor is made up of a sharp pointed metal (usually copper metal, as it is a very good conductor) connected directly to the ground. It is placed higher than the roof so that if lightning strikes, it strikes the conductor before it can reach the house. It should be pointed because when the negative charge is discharged by the cloud, it will first strike the pointed tip of the lightning conductor and quickly travel to the earth.
[15] Beta rays emitted by a radioactive material are –
A.
The electrons orbiting around the nucleus
B.
Charged particles emitted by nucleus
C.
Neutral particles
D.
Electromagnetic radiations
Ans:
Charged particles emitted by nucleus
Explanation :
A beta ray is a high-energy, high-speed electron (negatively charged) or positron (positively charged) emitted in the radioactive decay of an atomic nucleus, such as a potassium-40 nucleus, in the process of beta decay.
[16] What is the principle of a life Jacket'?
A.
It provides oxygen to a drowning person
B.
It increases the volume of the person to keep him afloat
C.
It decreases the volume of the person to keep him afloat
D.
The person can sit on it like a raft
Ans:
It increases the volume of the person to keep him afloat
Explanation :
The upward-pushing force that keeps things afloat is called buoyancy. For an object to float it must be able to equal its own weight by displacing enough water. A life jacket is mainly filled with gas which has a very low mass. As such when worn by a person, it acts to significantly increase their volume for only a very small increase in their mass.
[17] Steam at 100°C causes more severe burns than water at 100° C because –
A.
steam has no specific heat capacity
B.
steam has latent heat of vaporization
C.
water has no specific heat capacity
D.
water has latent heat of fusion
Ans:
steam has latent heat of vaporization
Explanation :
It is because steam releases its latent heat as it condenses, which is substantial. The heat of vaporization of steam is over 2000 J per gram. And when it releases that it's then 100 degree water, the same as boiling water.
[18] Ice cubes are added to a glass of pure water and a glass of pure alcohol. The ice would be –
A.
at a higher level in water
B.
at a higher level in alcohol
C.
at the same level in both
D.
floating in alcohol and sinking in water
Ans:
at a higher level in water
Explanation :
Density of water is approx 1 g/ml; Density of Ice is approx 0.93g/ml; and Density of 100% pure ethanol is 0.79g/ml. So the density of ice cubes is lesser than water, but higher than alcohol. So it will float in water, but sink in alcohol.
[19] Indicate the false statement about the resistance of a wire –
A.
it depends on material of wire
B.
it is directly proportional to the length of wire
C.
it is directly proportional to the area of cross-section of wire
D.
resistance of metallic wire increases with increase in temperature
Ans:
it is directly proportional to the area of cross-section of wire
Explanation :
The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it The SI unit of resistance is ohm.
[20] A metal ball and a rubber ball, both having the same mass, strike a wall normally with the same velocity. The rubber ball rebounds and the metal ball does not rebound. It can be concluded that –
A.
The rubber ball suffers greater change in momentum
B.
The metal ball suffers greater change in momentum
C.
Both suffer the same change in momentum
D.
The initial momentum of the rubber ball is greater than that of the metal ball
Ans:
The rubber ball suffers greater change in momentum
Explanation :
As per the question, the rubber ball rebounds while the metal ball does not. So if m and v be the mass and velocity respectively, the change in momentum of rubber ball = 2 mv (in magnitude) However, the change in momentum of the metal ball = mv The rubber ball suffers almost twice the change in momentum as experienced by the metal ball.
[21] In a conductor –
A.
there is no conduction band
B.
the forbidden energy gap is very wide
C.
the forbidden energy gap is very narrow
D.
the valence band and the conduction band overlap each other
Ans:
the valence band and the conduction band overlap each other
Explanation :
In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band. Conduction energy band
[22] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because –
A.
Mercury is a metal
B.
Density of mercury is greater than that of water
C.
Cohesion of mercury is greater than its adhesion with glass
D.
Cohesion of water is greater than its adhesion with glass
Ans:
Cohesion of mercury is greater than its adhesion with glass
Explanation :
When liquid is placed on a smooth surface like glass plate, the relative strengths of the cohesive and adhesive forces acting on that liquid determine the shape it will take (and whether or not it will wet the surface). If the adhesive forces between a liquid and a surface are stronger, they will pull the liquid down, causing it to wet the surface.
[23] The mass-energy relation is the outcome of –
A.
quantum theory
B.
general theory of relativity
C.
field theory of energy
D.
special theory of relativity
Ans:
special theory of relativity
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
The choke primarily serves to limit current flow to the correct level for the tube. It also can be used during startup to provide an inductive 'kick' forming a momentary higher-voltage pulse to start the lamp.
[14] To prevent damage from lightning, lightning conductors are used on tall structures. The lightning conductor –
A.
should be made of a good conductor but can be of any shape
B.
should be in the form of a vertical rod
C.
can be of any shape
D.
should be made of a good conductor like copper with sharp-pointed edges
Ans:
should be made of a good conductor like copper with sharp-pointed edges
Explanation :
A lightning conductor is made up of a sharp pointed metal (usually copper metal, as it is a very good conductor) connected directly to the ground. It is placed higher than the roof so that if lightning strikes, it strikes the conductor before it can reach the house. It should be pointed because when the negative charge is discharged by the cloud, it will first strike the pointed tip of the lightning conductor and quickly travel to the earth.
[15] Beta rays emitted by a radioactive material are –
A.
The electrons orbiting around the nucleus
B.
Charged particles emitted by nucleus
C.
Neutral particles
D.
Electromagnetic radiations
Ans:
Charged particles emitted by nucleus
Explanation :
A beta ray is a high-energy, high-speed electron (negatively charged) or positron (positively charged) emitted in the radioactive decay of an atomic nucleus, such as a potassium-40 nucleus, in the process of beta decay.
[16] What is the principle of a life Jacket'?
A.
It provides oxygen to a drowning person
B.
It increases the volume of the person to keep him afloat
C.
It decreases the volume of the person to keep him afloat
D.
The person can sit on it like a raft
Ans:
It increases the volume of the person to keep him afloat
Explanation :
The upward-pushing force that keeps things afloat is called buoyancy. For an object to float it must be able to equal its own weight by displacing enough water. A life jacket is mainly filled with gas which has a very low mass. As such when worn by a person, it acts to significantly increase their volume for only a very small increase in their mass.
[17] Steam at 100°C causes more severe burns than water at 100° C because –
A.
steam has no specific heat capacity
B.
steam has latent heat of vaporization
C.
water has no specific heat capacity
D.
water has latent heat of fusion
Ans:
steam has latent heat of vaporization
Explanation :
It is because steam releases its latent heat as it condenses, which is substantial. The heat of vaporization of steam is over 2000 J per gram. And when it releases that it's then 100 degree water, the same as boiling water.
[18] Ice cubes are added to a glass of pure water and a glass of pure alcohol. The ice would be –
A.
at a higher level in water
B.
at a higher level in alcohol
C.
at the same level in both
D.
floating in alcohol and sinking in water
Ans:
at a higher level in water
Explanation :
Density of water is approx 1 g/ml; Density of Ice is approx 0.93g/ml; and Density of 100% pure ethanol is 0.79g/ml. So the density of ice cubes is lesser than water, but higher than alcohol. So it will float in water, but sink in alcohol.
[19] Indicate the false statement about the resistance of a wire –
A.
it depends on material of wire
B.
it is directly proportional to the length of wire
C.
it is directly proportional to the area of cross-section of wire
D.
resistance of metallic wire increases with increase in temperature
Ans:
it is directly proportional to the area of cross-section of wire
Explanation :
The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it The SI unit of resistance is ohm.
[20] A metal ball and a rubber ball, both having the same mass, strike a wall normally with the same velocity. The rubber ball rebounds and the metal ball does not rebound. It can be concluded that –
A.
The rubber ball suffers greater change in momentum
B.
The metal ball suffers greater change in momentum
C.
Both suffer the same change in momentum
D.
The initial momentum of the rubber ball is greater than that of the metal ball
Ans:
The rubber ball suffers greater change in momentum
Explanation :
As per the question, the rubber ball rebounds while the metal ball does not. So if m and v be the mass and velocity respectively, the change in momentum of rubber ball = 2 mv (in magnitude) However, the change in momentum of the metal ball = mv The rubber ball suffers almost twice the change in momentum as experienced by the metal ball.
[21] In a conductor –
A.
there is no conduction band
B.
the forbidden energy gap is very wide
C.
the forbidden energy gap is very narrow
D.
the valence band and the conduction band overlap each other
Ans:
the valence band and the conduction band overlap each other
Explanation :
In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band. Conduction energy band
[22] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because –
A.
Mercury is a metal
B.
Density of mercury is greater than that of water
C.
Cohesion of mercury is greater than its adhesion with glass
D.
Cohesion of water is greater than its adhesion with glass
Ans:
Cohesion of mercury is greater than its adhesion with glass
Explanation :
When liquid is placed on a smooth surface like glass plate, the relative strengths of the cohesive and adhesive forces acting on that liquid determine the shape it will take (and whether or not it will wet the surface). If the adhesive forces between a liquid and a surface are stronger, they will pull the liquid down, causing it to wet the surface.
[23] The mass-energy relation is the outcome of –
A.
quantum theory
B.
general theory of relativity
C.
field theory of energy
D.
special theory of relativity
Ans:
special theory of relativity
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
A beta ray is a high-energy, high-speed electron (negatively charged) or positron (positively charged) emitted in the radioactive decay of an atomic nucleus, such as a potassium-40 nucleus, in the process of beta decay.
[16] What is the principle of a life Jacket'?
A.
It provides oxygen to a drowning person
B.
It increases the volume of the person to keep him afloat
C.
It decreases the volume of the person to keep him afloat
D.
The person can sit on it like a raft
Ans:
It increases the volume of the person to keep him afloat
Explanation :
The upward-pushing force that keeps things afloat is called buoyancy. For an object to float it must be able to equal its own weight by displacing enough water. A life jacket is mainly filled with gas which has a very low mass. As such when worn by a person, it acts to significantly increase their volume for only a very small increase in their mass.
[17] Steam at 100°C causes more severe burns than water at 100° C because –
A.
steam has no specific heat capacity
B.
steam has latent heat of vaporization
C.
water has no specific heat capacity
D.
water has latent heat of fusion
Ans:
steam has latent heat of vaporization
Explanation :
It is because steam releases its latent heat as it condenses, which is substantial. The heat of vaporization of steam is over 2000 J per gram. And when it releases that it's then 100 degree water, the same as boiling water.
[18] Ice cubes are added to a glass of pure water and a glass of pure alcohol. The ice would be –
A.
at a higher level in water
B.
at a higher level in alcohol
C.
at the same level in both
D.
floating in alcohol and sinking in water
Ans:
at a higher level in water
Explanation :
Density of water is approx 1 g/ml; Density of Ice is approx 0.93g/ml; and Density of 100% pure ethanol is 0.79g/ml. So the density of ice cubes is lesser than water, but higher than alcohol. So it will float in water, but sink in alcohol.
[19] Indicate the false statement about the resistance of a wire –
A.
it depends on material of wire
B.
it is directly proportional to the length of wire
C.
it is directly proportional to the area of cross-section of wire
D.
resistance of metallic wire increases with increase in temperature
Ans:
it is directly proportional to the area of cross-section of wire
Explanation :
The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it The SI unit of resistance is ohm.
[20] A metal ball and a rubber ball, both having the same mass, strike a wall normally with the same velocity. The rubber ball rebounds and the metal ball does not rebound. It can be concluded that –
A.
The rubber ball suffers greater change in momentum
B.
The metal ball suffers greater change in momentum
C.
Both suffer the same change in momentum
D.
The initial momentum of the rubber ball is greater than that of the metal ball
Ans:
The rubber ball suffers greater change in momentum
Explanation :
As per the question, the rubber ball rebounds while the metal ball does not. So if m and v be the mass and velocity respectively, the change in momentum of rubber ball = 2 mv (in magnitude) However, the change in momentum of the metal ball = mv The rubber ball suffers almost twice the change in momentum as experienced by the metal ball.
[21] In a conductor –
A.
there is no conduction band
B.
the forbidden energy gap is very wide
C.
the forbidden energy gap is very narrow
D.
the valence band and the conduction band overlap each other
Ans:
the valence band and the conduction band overlap each other
Explanation :
In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band. Conduction energy band
[22] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because –
A.
Mercury is a metal
B.
Density of mercury is greater than that of water
C.
Cohesion of mercury is greater than its adhesion with glass
D.
Cohesion of water is greater than its adhesion with glass
Ans:
Cohesion of mercury is greater than its adhesion with glass
Explanation :
When liquid is placed on a smooth surface like glass plate, the relative strengths of the cohesive and adhesive forces acting on that liquid determine the shape it will take (and whether or not it will wet the surface). If the adhesive forces between a liquid and a surface are stronger, they will pull the liquid down, causing it to wet the surface.
[23] The mass-energy relation is the outcome of –
A.
quantum theory
B.
general theory of relativity
C.
field theory of energy
D.
special theory of relativity
Ans:
special theory of relativity
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
It is because steam releases its latent heat as it condenses, which is substantial. The heat of vaporization of steam is over 2000 J per gram. And when it releases that it's then 100 degree water, the same as boiling water.
[18] Ice cubes are added to a glass of pure water and a glass of pure alcohol. The ice would be –
A.
at a higher level in water
B.
at a higher level in alcohol
C.
at the same level in both
D.
floating in alcohol and sinking in water
Ans:
at a higher level in water
Explanation :
Density of water is approx 1 g/ml; Density of Ice is approx 0.93g/ml; and Density of 100% pure ethanol is 0.79g/ml. So the density of ice cubes is lesser than water, but higher than alcohol. So it will float in water, but sink in alcohol.
[19] Indicate the false statement about the resistance of a wire –
A.
it depends on material of wire
B.
it is directly proportional to the length of wire
C.
it is directly proportional to the area of cross-section of wire
D.
resistance of metallic wire increases with increase in temperature
Ans:
it is directly proportional to the area of cross-section of wire
Explanation :
The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it The SI unit of resistance is ohm.
[20] A metal ball and a rubber ball, both having the same mass, strike a wall normally with the same velocity. The rubber ball rebounds and the metal ball does not rebound. It can be concluded that –
A.
The rubber ball suffers greater change in momentum
B.
The metal ball suffers greater change in momentum
C.
Both suffer the same change in momentum
D.
The initial momentum of the rubber ball is greater than that of the metal ball
Ans:
The rubber ball suffers greater change in momentum
Explanation :
As per the question, the rubber ball rebounds while the metal ball does not. So if m and v be the mass and velocity respectively, the change in momentum of rubber ball = 2 mv (in magnitude) However, the change in momentum of the metal ball = mv The rubber ball suffers almost twice the change in momentum as experienced by the metal ball.
[21] In a conductor –
A.
there is no conduction band
B.
the forbidden energy gap is very wide
C.
the forbidden energy gap is very narrow
D.
the valence band and the conduction band overlap each other
Ans:
the valence band and the conduction band overlap each other
Explanation :
In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band. Conduction energy band
[22] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because –
A.
Mercury is a metal
B.
Density of mercury is greater than that of water
C.
Cohesion of mercury is greater than its adhesion with glass
D.
Cohesion of water is greater than its adhesion with glass
Ans:
Cohesion of mercury is greater than its adhesion with glass
Explanation :
When liquid is placed on a smooth surface like glass plate, the relative strengths of the cohesive and adhesive forces acting on that liquid determine the shape it will take (and whether or not it will wet the surface). If the adhesive forces between a liquid and a surface are stronger, they will pull the liquid down, causing it to wet the surface.
[23] The mass-energy relation is the outcome of –
A.
quantum theory
B.
general theory of relativity
C.
field theory of energy
D.
special theory of relativity
Ans:
special theory of relativity
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it The SI unit of resistance is ohm.
[20] A metal ball and a rubber ball, both having the same mass, strike a wall normally with the same velocity. The rubber ball rebounds and the metal ball does not rebound. It can be concluded that –
A.
The rubber ball suffers greater change in momentum
B.
The metal ball suffers greater change in momentum
C.
Both suffer the same change in momentum
D.
The initial momentum of the rubber ball is greater than that of the metal ball
Ans:
The rubber ball suffers greater change in momentum
Explanation :
As per the question, the rubber ball rebounds while the metal ball does not. So if m and v be the mass and velocity respectively, the change in momentum of rubber ball = 2 mv (in magnitude) However, the change in momentum of the metal ball = mv The rubber ball suffers almost twice the change in momentum as experienced by the metal ball.
[21] In a conductor –
A.
there is no conduction band
B.
the forbidden energy gap is very wide
C.
the forbidden energy gap is very narrow
D.
the valence band and the conduction band overlap each other
Ans:
the valence band and the conduction band overlap each other
Explanation :
In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band. Conduction energy band
[22] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because –
A.
Mercury is a metal
B.
Density of mercury is greater than that of water
C.
Cohesion of mercury is greater than its adhesion with glass
D.
Cohesion of water is greater than its adhesion with glass
Ans:
Cohesion of mercury is greater than its adhesion with glass
Explanation :
When liquid is placed on a smooth surface like glass plate, the relative strengths of the cohesive and adhesive forces acting on that liquid determine the shape it will take (and whether or not it will wet the surface). If the adhesive forces between a liquid and a surface are stronger, they will pull the liquid down, causing it to wet the surface.
[23] The mass-energy relation is the outcome of –
A.
quantum theory
B.
general theory of relativity
C.
field theory of energy
D.
special theory of relativity
Ans:
special theory of relativity
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
In the case of a conductor, there is no forbidden energy gap. The conduction and valence energy bands overlap each other. Obviously, the electrons from the valence band can freely enter the conduction energy band. Conduction energy band
[22] On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because –
A.
Mercury is a metal
B.
Density of mercury is greater than that of water
C.
Cohesion of mercury is greater than its adhesion with glass
D.
Cohesion of water is greater than its adhesion with glass
Ans:
Cohesion of mercury is greater than its adhesion with glass
Explanation :
When liquid is placed on a smooth surface like glass plate, the relative strengths of the cohesive and adhesive forces acting on that liquid determine the shape it will take (and whether or not it will wet the surface). If the adhesive forces between a liquid and a surface are stronger, they will pull the liquid down, causing it to wet the surface.
[23] The mass-energy relation is the outcome of –
A.
quantum theory
B.
general theory of relativity
C.
field theory of energy
D.
special theory of relativity
Ans:
special theory of relativity
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
Special theory of relativity postulates that the speed of light is a universal constant. We cannot reach speeds greater than the speed of light by the relativistic addition of velocities.
[24] Which set of conditions represents the easiest way to liquefy a gas?
A.
Low temperature and high pressure
B.
High temperature and low pressure
C.
Low temperat.ure and low pressure
D.
High temperature and high pressure
Ans:
Low temperature and high pressure
Explanation :
Low temperature and high pressure set of conditions represents the easiest way to liquefy a gas. Liquefaction of gases is physical conversion of a gas into a liquid state (condensation). The processes are used for scientific, industrial and commercial purposes. Many gases can be put into a liquid state at normal atmospheric pressure by simple cooling; a few, such as carbon dioxide, require pressurization as well.
[25] A person can jump higher on the moon's surface than on the earth because –
A.
the moon's surface is rough
B.
the acceleration due to gravity in moon is smaller than that on the earth.
C.
the moon is cooler than earth
D.
the moon has no atmosphere
Ans:
the acceleration due to gravity in moon is smaller than that on the earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.
Explanation :
The acceleration due to the gravitational field of moon (g' = 1.62631 ms-2) is one-sixth of the acceleration due to gravity on the Earth. So the weight of the same body is also 1/6th on moon in comparison to that on the surface of the earth. It is due to this reason; a man can jump six times higher on moon than on earth.