PHYSICS
UPSC CSE Physics MCQs
1. When tennis ball is released with spin it becomes difficult to hit it back in the designed direction because
(A) we have to apply suitable torque
(B) we have to apply suitable force
(C) we have to apply suitable potential energy
(D) we have to apply suitable kinetic energy
Ans: A
2. The definition of kinetic energy for a rotating body about a fixed axis requires
(A) Moment of inertia and angular velocity
(B) Moment of inertia only
(C) Angular velocity only
(D) None of these
Ans: A
3. A force acts on a body at rest and accelerates the same, then which of the following is true?
(A) The greater the inertia the greater the acceleration
(B) The greater the inertia the lesser the acceleration
(C) The acceleration is independent of inertia
(D) All of the three statements are incorrect
Ans: B
4. Which of the following statement is true?
(A) Torque plays the same role in rotational motion as force plays in translational motion
(B) Torque does not play any role m rotational motion
(C) Torque plays the same role in rotational motion as momentum plays in translational motion
(D) Torque role is to keep the angular velocity constant
Ans: A
5. A particle is going round a circular path with constant speed. Therefore it is moving with
(A) Constant velocity
(B) Constant acceleration
(C) Constant momentum
(D) None of these
Ans: D
6. The force required to maintain a body at constant speed in free space is equal to
(A) The kinetic energy of the body
(B) Zero energy
(C) The mass of the body
(D) The weight of the body
Ans: B
7. The moment of inertia of a ring is minimum about an axis
(A) passing through its centre and perpendicular to its plane
(B) passing through its edge and perpendicular to its plane
(C) tangential in the plane of the ring
(D) coinciding with diameter
Ans: D
8. In a direct collision, the direction of motion of both the sphere is along the common normal at the point of contact?
(A) before collision
(B) after collision
(C) before and after collision
(D) none of the above
Ans: C
9. The best example of impulse force is
(A) a bullet hitting a target
(B) a man pushing a cart
(C) a boat being rowed
(D) a car being towed
Ans: A
10. Hooke's law obeys in the
(A) Permanent set range
(B) Elastic limit
(C) Elastic range
(D) Plastic range
Ans: C
11. Poisson's ratio defines
(A) ratio of longitudinal stress to linear strain
(B) ratio of area stress to volume strain
(C) ratio of tangential stress to shear strain
(D) ratio of lateral strain to tangential strain
Ans: D
12. In a cantilever as it is loaded at one end, the neutral filament of the beam
(A) extends its length
(B) shortens its length
(C) remains constant
(D) changes its length non uniformly
Ans: C
13. Reynold number is used in the context of
(A) Surface tension
(B) Pressure
( C) Viscocity
(D) Gravity
Ans: C
14. Acceleration due to gravity for earth is
(A) large at poles and small at equator
(B) small at poles and large at equator
(C) constant at poles and at equator
(D) zero at poles and maximum at equator
Ans: A
15. As the bore radius is reduced in a capillary rise method for a given liquid
(A) height of the liquid column decreases
(B) height of the liquid column increases
(C) height of the liquid column remains constant
(D) meniscus becomes concave to convex
Ans: B
16. Angle of contact value for water with glass is
(A) between 180° and 90°
(B) greater than 90° and less than 140°
(C) less than 90° and greater than 10°
(D) less than 10°
Ans: C
(A) we have to apply suitable torque
(B) we have to apply suitable force
(C) we have to apply suitable potential energy
(D) we have to apply suitable kinetic energy
Ans: A
2. The definition of kinetic energy for a rotating body about a fixed axis requires
(A) Moment of inertia and angular velocity
(B) Moment of inertia only
(C) Angular velocity only
(D) None of these
Ans: A
3. A force acts on a body at rest and accelerates the same, then which of the following is true?
(A) The greater the inertia the greater the acceleration
(B) The greater the inertia the lesser the acceleration
(C) The acceleration is independent of inertia
(D) All of the three statements are incorrect
Ans: B
4. Which of the following statement is true?
(A) Torque plays the same role in rotational motion as force plays in translational motion
(B) Torque does not play any role m rotational motion
(C) Torque plays the same role in rotational motion as momentum plays in translational motion
(D) Torque role is to keep the angular velocity constant
Ans: A
5. A particle is going round a circular path with constant speed. Therefore it is moving with
(A) Constant velocity
(B) Constant acceleration
(C) Constant momentum
(D) None of these
Ans: D
6. The force required to maintain a body at constant speed in free space is equal to
(A) The kinetic energy of the body
(B) Zero energy
(C) The mass of the body
(D) The weight of the body
Ans: B
7. The moment of inertia of a ring is minimum about an axis
(A) passing through its centre and perpendicular to its plane
(B) passing through its edge and perpendicular to its plane
(C) tangential in the plane of the ring
(D) coinciding with diameter
Ans: D
8. In a direct collision, the direction of motion of both the sphere is along the common normal at the point of contact?
(A) before collision
(B) after collision
(C) before and after collision
(D) none of the above
Ans: C
9. The best example of impulse force is
(A) a bullet hitting a target
(B) a man pushing a cart
(C) a boat being rowed
(D) a car being towed
Ans: A
10. Hooke's law obeys in the
(A) Permanent set range
(B) Elastic limit
(C) Elastic range
(D) Plastic range
Ans: C
11. Poisson's ratio defines
(A) ratio of longitudinal stress to linear strain
(B) ratio of area stress to volume strain
(C) ratio of tangential stress to shear strain
(D) ratio of lateral strain to tangential strain
Ans: D
12. In a cantilever as it is loaded at one end, the neutral filament of the beam
(A) extends its length
(B) shortens its length
(C) remains constant
(D) changes its length non uniformly
Ans: C
13. Reynold number is used in the context of
(A) Surface tension
(B) Pressure
( C) Viscocity
(D) Gravity
Ans: C
14. Acceleration due to gravity for earth is
(A) large at poles and small at equator
(B) small at poles and large at equator
(C) constant at poles and at equator
(D) zero at poles and maximum at equator
Ans: A
15. As the bore radius is reduced in a capillary rise method for a given liquid
(A) height of the liquid column decreases
(B) height of the liquid column increases
(C) height of the liquid column remains constant
(D) meniscus becomes concave to convex
Ans: B
16. Angle of contact value for water with glass is
(A) between 180° and 90°
(B) greater than 90° and less than 140°
(C) less than 90° and greater than 10°
(D) less than 10°
Ans: C
17. Consider the statements:
Assertion (A) : The osmatic pressure of electrolytes is much higher than that of nonelectrolytes under same temperature and concentration
Reason (R): Dissociation of the electrolyte in solution.
Select the answer according to coding scheme.
(A) (A) and (R) are true
(B) (A) and (R) are false
(C) (A) is true but (R) is false
(D) (A) is false but (R) is true
Ans: A
18. The density of a gas is reduced to 1/4th of its value. The rate of diffusion
(A) decreases four times
(B) increases four times
(C) decreases two times
(D) increases two times
Ans: D
19. When a substance is dissolved in a liquid, the boiling point of a liquid is
(A) unchanged
(B) raised
(C) lowered
(D) none of the above
Ans: B
20. Which of the following is correct?
The capillary rise method suffers from a number of drawbacks
(A) The angle of contact is taken to be zero
(B) The tube may not be of uniform area of cross section
(C) The table may not be clean
(D) All of the above
Ans: D
21. The viscous force experienced by a falling sphere in a highly viscous liquid depends on
(A) the terminal velocity of the ball
(B) the radius of the ball
(C) the coefficient of viscosity of the liquid
(D) all of the above
Ans: D
22. A physical process during which there is neither gain nor loss of heat from the system is called
(A) adiabatic
(B) isothermal
(C) thermo dynamical
(D) entropy
Ans: A
Assertion (A) : The osmatic pressure of electrolytes is much higher than that of nonelectrolytes under same temperature and concentration
Reason (R): Dissociation of the electrolyte in solution.
Select the answer according to coding scheme.
(A) (A) and (R) are true
(B) (A) and (R) are false
(C) (A) is true but (R) is false
(D) (A) is false but (R) is true
Ans: A
18. The density of a gas is reduced to 1/4th of its value. The rate of diffusion
(A) decreases four times
(B) increases four times
(C) decreases two times
(D) increases two times
Ans: D
19. When a substance is dissolved in a liquid, the boiling point of a liquid is
(A) unchanged
(B) raised
(C) lowered
(D) none of the above
Ans: B
20. Which of the following is correct?
The capillary rise method suffers from a number of drawbacks
(A) The angle of contact is taken to be zero
(B) The tube may not be of uniform area of cross section
(C) The table may not be clean
(D) All of the above
Ans: D
21. The viscous force experienced by a falling sphere in a highly viscous liquid depends on
(A) the terminal velocity of the ball
(B) the radius of the ball
(C) the coefficient of viscosity of the liquid
(D) all of the above
Ans: D
22. A physical process during which there is neither gain nor loss of heat from the system is called
(A) adiabatic
(B) isothermal
(C) thermo dynamical
(D) entropy
Ans: A
23. The first law of thermodynamics is a statement which implies that
(A) no heat enters or leaves a system
(B) the temperature remains constant
(C ) all work is mechanical
(D) energy is conserved
Ans: D
24. The amount of heat energy radiated per second by a surface depends upon
(A) area of the surface
(B) difference of temperature between the surface and its surroundings
(C ) nature of the surface
(D) all the above
Ans: D
25. If the pressure on the gas is increased from P to 2P atmosphere, then the heat conductivity
(A) decreases
(B) increases
(C ) remains constant
(D) decreases logarithmically
Ans: C
26. If p - Calories of heat energy is incident on a body and absorb q - calories, its coefficient of absorption is
(A) p/q
(B) p - q
(C) q /p
(D) q + p
Ans: A
27. When a body has the same temperature as that of its surroundings?
(A) Both body do not radiate heat
(B) It radiates same quantity of heat as it receives from surrounding
(C) It radiates less quantity of heat as it receives from the surrounding
(D) It radiates more quantity of heat as it receives from the surrounding
Ans: D
28.The internal energy of a thermodynamical system consisting of an ideal gas is
(A) Kinetic energy only
(B) Potential energy only
(C) Gravitational energy only
(D) Partially kinetic and partially potential energy
Ans: A
29. Critical temperature is one
(A) above which the gaseous system remains the same
(B) above which the gaseous system remains in liquid state
(C) above which the gaseous system remains in solid state
(D) below which the gaseous system remains the same
Ans: A
30. Temperature of inversion means
(A) Temperature above which temperature remaining constant
(B) Temperature below which temperature is zero
(C ) Temperature above which temperature increases
(D) Critical temperature
Ans: C
31. Refrigeration works as a
(A) Carnot's engine in a heat engine
(B) Carnot's engine in a reversible process
(C ) Carnot's engine in an irreversible process
(D) Carnot's engine without adiabatic process
Ans: C
32. Third law of thermodynamics
(A) entropy cannot be absolutely measured
(B) at gaseous state, entropy is low compared that in the liquid state
(C) at absolute zero temperature, entropy is zero
(D) at absolute zero temperature, entropy is maximum
Ans: C
33. When a train crosses a person standing on the platform, the pitch of the whistle of the train?
(A) increases
(B) decreases
(C ) increases and then decreases
(D) decreases and then increases
Ans: C
34. In a sonometer, a particular length vibrates at a frequency. If the frequency of the same length is to be doubled, the tension of the string must be
(A) decreased by a factor of two
(B) decreased by a factor of four
(C) increased by a factor of two
(D) increased by a factor of four
Ans: D
35. A stretched string of length 92 cm is divided into three segments whose frequencies are in the ratio 1 : 3 : 5. Then their lengths are in the ratio
(A) 12 cm, 20 cm, 60 cm
(B) 20 cm, 60 cm, 12 cm
(C) 20 cm, 12 cm, 60 cm
(D) 60 cm, 20 cm, 12 cm
Ans: D
36. Very small differences in frequencies can be measured using
(A) Resonance
(B) Doppler effect
(C) Ultrasonics
(D) Beats
Ans: D
37. Doppler shift in frequencies is due to the observer receiving the waves
(A) ahead of time
(B) behind time
(C) ahead of or behind time
(D) in time
Ans: C
(A) no heat enters or leaves a system
(B) the temperature remains constant
(C ) all work is mechanical
(D) energy is conserved
Ans: D
24. The amount of heat energy radiated per second by a surface depends upon
(A) area of the surface
(B) difference of temperature between the surface and its surroundings
(C ) nature of the surface
(D) all the above
Ans: D
25. If the pressure on the gas is increased from P to 2P atmosphere, then the heat conductivity
(A) decreases
(B) increases
(C ) remains constant
(D) decreases logarithmically
Ans: C
26. If p - Calories of heat energy is incident on a body and absorb q - calories, its coefficient of absorption is
(A) p/q
(B) p - q
(C) q /p
(D) q + p
Ans: A
27. When a body has the same temperature as that of its surroundings?
(A) Both body do not radiate heat
(B) It radiates same quantity of heat as it receives from surrounding
(C) It radiates less quantity of heat as it receives from the surrounding
(D) It radiates more quantity of heat as it receives from the surrounding
Ans: D
28.The internal energy of a thermodynamical system consisting of an ideal gas is
(A) Kinetic energy only
(B) Potential energy only
(C) Gravitational energy only
(D) Partially kinetic and partially potential energy
Ans: A
29. Critical temperature is one
(A) above which the gaseous system remains the same
(B) above which the gaseous system remains in liquid state
(C) above which the gaseous system remains in solid state
(D) below which the gaseous system remains the same
Ans: A
30. Temperature of inversion means
(A) Temperature above which temperature remaining constant
(B) Temperature below which temperature is zero
(C ) Temperature above which temperature increases
(D) Critical temperature
Ans: C
31. Refrigeration works as a
(A) Carnot's engine in a heat engine
(B) Carnot's engine in a reversible process
(C ) Carnot's engine in an irreversible process
(D) Carnot's engine without adiabatic process
Ans: C
32. Third law of thermodynamics
(A) entropy cannot be absolutely measured
(B) at gaseous state, entropy is low compared that in the liquid state
(C) at absolute zero temperature, entropy is zero
(D) at absolute zero temperature, entropy is maximum
Ans: C
33. When a train crosses a person standing on the platform, the pitch of the whistle of the train?
(A) increases
(B) decreases
(C ) increases and then decreases
(D) decreases and then increases
Ans: C
34. In a sonometer, a particular length vibrates at a frequency. If the frequency of the same length is to be doubled, the tension of the string must be
(A) decreased by a factor of two
(B) decreased by a factor of four
(C) increased by a factor of two
(D) increased by a factor of four
Ans: D
35. A stretched string of length 92 cm is divided into three segments whose frequencies are in the ratio 1 : 3 : 5. Then their lengths are in the ratio
(A) 12 cm, 20 cm, 60 cm
(B) 20 cm, 60 cm, 12 cm
(C) 20 cm, 12 cm, 60 cm
(D) 60 cm, 20 cm, 12 cm
Ans: D
36. Very small differences in frequencies can be measured using
(A) Resonance
(B) Doppler effect
(C) Ultrasonics
(D) Beats
Ans: D
37. Doppler shift in frequencies is due to the observer receiving the waves
(A) ahead of time
(B) behind time
(C) ahead of or behind time
(D) in time
Ans: C
38. For good accoustics of a hall
(A) time of reverberation be large
(B) time of reverberation be small
(C) time of reverberation be zero
(D) time of reverberation be infinite
Ans: B
39. The capacitance of the cylindrical capacitor is directly proportional to
(A) length of the condenser
(B) radius of the condenser
(C) distance between coaxial cylinder
(D) diameter of the condenser
Ans: A
40. What is the potential at three different points (A, B, C) in equipotential surface?
(A) A is greater than B and C
(B) B is greater than C and A
(C) C is greater than A and B
(D) Equal in A, B and C
Ans: D
41. Heat produced in an electric conductor is
(A) directly proportional to its resistance
(B) inversely proportion to its resistance
(C) inversely proportional to the current
(D) inversely proportional to square of the current
Ans: A
42. The best instrument for the accurate measurement of the E.M.F. of a cell is
(A) voltmeter
(B) ammeter
(C) potentiometer
(D) Galvanometer
Ans: C
43. Newton's rings are
(A) diffraction bands
(B) diffraction bands and interference fringes
(C) interference fringes
(D) none of the above
Ans: C
44. In Frenel form of diffraction, the distance between be screen and the obstacle is
(A) zero
(B) infinite
(C) finite
(D) none of the above
Ans: C
45. In case of Fraunhofer diffraction, we get fringed image of
(A) source
(B) obstacle
(C) aperture
(D) none of the above
Ans: A
(A) time of reverberation be large
(B) time of reverberation be small
(C) time of reverberation be zero
(D) time of reverberation be infinite
Ans: B
39. The capacitance of the cylindrical capacitor is directly proportional to
(A) length of the condenser
(B) radius of the condenser
(C) distance between coaxial cylinder
(D) diameter of the condenser
Ans: A
40. What is the potential at three different points (A, B, C) in equipotential surface?
(A) A is greater than B and C
(B) B is greater than C and A
(C) C is greater than A and B
(D) Equal in A, B and C
Ans: D
41. Heat produced in an electric conductor is
(A) directly proportional to its resistance
(B) inversely proportion to its resistance
(C) inversely proportional to the current
(D) inversely proportional to square of the current
Ans: A
42. The best instrument for the accurate measurement of the E.M.F. of a cell is
(A) voltmeter
(B) ammeter
(C) potentiometer
(D) Galvanometer
Ans: C
43. Newton's rings are
(A) diffraction bands
(B) diffraction bands and interference fringes
(C) interference fringes
(D) none of the above
Ans: C
44. In Frenel form of diffraction, the distance between be screen and the obstacle is
(A) zero
(B) infinite
(C) finite
(D) none of the above
Ans: C
45. In case of Fraunhofer diffraction, we get fringed image of
(A) source
(B) obstacle
(C) aperture
(D) none of the above
Ans: A
46. A device which produces plane polarized light is called
(A) polarizer
(B) detector
(C) analyser
(D) none of the above
Ans: A
47. Nicol prism is made by
(A) Calcite crystal
(B) Bauxite crystal
(C) KCl crystal
(D) None of the above
Ans: A
48. The phenomenon of rotating the plane of vibration of polarised light when passed through the substance is known as
(A) Polarisation
(B) Optical activity
(C) Double refraction
(D) None of the above
Ans: B
49. As a result of interference between two waves, energy is
(A) lost
(B) created at certain points and destroyed at others
(C) created
(D) redistributed
Ans: D
50. Of the two statements given below, one is Assertion statement; the other is Reason. Study them, and select a suitable answer using the codes given below :
Assertion (A) Information obtained from Hubble space telescope show that universe, as a whole is expanding.
Reason (R) The colour of the distant star and appeared red on earth, showing a shift towards lower frequency of spectrum.
(A) (A) is true, but (R) is not the reason for it.
(B) (A) not true
(C ) (A) is true and (R) is the reason for it
(D)(R) not true
Ans: C
51. One of the devices to produce plane polarised light is
(A) a nicol prism
(B) a crystal
(C) a biprism
(D) a half wave plate
Ans: A
52. Optically active substances are those substances which
(A) produce polarised light
(B) rotate the plane of polarisation of polarised light
(C) produce double refraction
(D) convert a plane polarised light
Ans: B
53. Polarisation of light proves the
(A) Corpuscular nature of light
(B) Quantum nature of light
(C ) Transverse wave nature of light
(C) Longitudinal wave nature of light
Ans: C
54. In double slit experiment, for light of which colour the fringe width will be minimum?
(A) Violet
(B) Red
(C) Green
(D) Yellow
Ans: A
55. In Raman effect, the scattered light contains
(A) original wavelength only
(B) original wavelength and increased wavelength
(C) original wavelength and decreased wavelength
(D) original wavelength and both increased and decreased wavelengths
Ans: D
56. The characteristic property of a laser beam is
(A) Coherent beam only
(B) Monochromatic beam only
(C) A diverging beam only
(D) Coherent and monochromatic both
Ans: D
57. The transition involving electro magnetic radiation are possible between two energy levels due to
(A) Induced absorption emission only
(B) Spontaneous emission only
(C) Stimulated emission only
(D) All the above
Ans: D
58. For recording an ultra violet spectrum of shorter wavelength
(A) Plane Transmission grating is used
(B) Concave reflection grating is used
(C) Crystal is used
(D) Prism is used
Ans: B
59. When ultra violet light is used for illumination,
(A) the resolving power of a telescope is increased
(B) the resolving power of a telescope is decreased
(C) the resolving power of a microscope is decreased
(D) the resolving power of a microscope is increased
Ans: D
60. Globar filament is a rod made of ________
(A) rare earth oxides
(B) carborundum
(C) copper
(D) semiconductor
Ans: B
61. In IR spectrometer lenses and mirrors are made of---
(A) quartz
(B) glass
(C) mineral salt
(D) calcite
Ans: C
62. A radical is Raman active, if there is a change in -----of the molecule during the application of an electric field
(A) dipole moment
(B) electrical polarizability
(C) bond length
(D) bond angle
Ans: B
63. If a molecule has a centre of symmetry, then Raman active vibrations are ----
(A) IR active
(B) IR inactive
(C) Microwave active
(D) Microwave inactive
Ans: B
64. The quality factor - Q of a laser cavity measure
(A) gain
(B) losses
(C) broadening
(D) population inversion
Ans: B
65. The pumping process is Ruby laser is by
(A) Optical means
(B) Electrical means
(C) Chemical means
(D) Gas dynamic means
Ans: A
66. The role of He atoms in He - Ne laser is to assist in the
(A) pumping process
(B) laser action
(C) laser oscillation
(D) population inversion
Ans: A
67. The dynamo dissipates 20 watt when it supplies a current of 4 ampere through it. The
terminal potential difference is 220V. The e.m.f. produced by the dynamo is
(A) 220 V
(B) 225V
(C) 230 V
(D) 240 V
Ans: B
68. When a material is used in a magnetic field B, a magnetic moment proportional to B but opposite in direction is induced. The material is
(A) Diamagnetic
(B) Paramagnetic
(C) Ferromagnetic
(D) Antimagnetic
Ans: A
69. When two equal and perfectly elastic spheres impinge directly,
(A) their velocities remain unchanged
(B) their velocities are changed
(C) their velocities are interchanged
(D) none of the above
Ans: C
(A) polarizer
(B) detector
(C) analyser
(D) none of the above
Ans: A
47. Nicol prism is made by
(A) Calcite crystal
(B) Bauxite crystal
(C) KCl crystal
(D) None of the above
Ans: A
48. The phenomenon of rotating the plane of vibration of polarised light when passed through the substance is known as
(A) Polarisation
(B) Optical activity
(C) Double refraction
(D) None of the above
Ans: B
49. As a result of interference between two waves, energy is
(A) lost
(B) created at certain points and destroyed at others
(C) created
(D) redistributed
Ans: D
50. Of the two statements given below, one is Assertion statement; the other is Reason. Study them, and select a suitable answer using the codes given below :
Assertion (A) Information obtained from Hubble space telescope show that universe, as a whole is expanding.
Reason (R) The colour of the distant star and appeared red on earth, showing a shift towards lower frequency of spectrum.
(A) (A) is true, but (R) is not the reason for it.
(B) (A) not true
(C ) (A) is true and (R) is the reason for it
(D)(R) not true
Ans: C
51. One of the devices to produce plane polarised light is
(A) a nicol prism
(B) a crystal
(C) a biprism
(D) a half wave plate
Ans: A
52. Optically active substances are those substances which
(A) produce polarised light
(B) rotate the plane of polarisation of polarised light
(C) produce double refraction
(D) convert a plane polarised light
Ans: B
53. Polarisation of light proves the
(A) Corpuscular nature of light
(B) Quantum nature of light
(C ) Transverse wave nature of light
(C) Longitudinal wave nature of light
Ans: C
54. In double slit experiment, for light of which colour the fringe width will be minimum?
(A) Violet
(B) Red
(C) Green
(D) Yellow
Ans: A
55. In Raman effect, the scattered light contains
(A) original wavelength only
(B) original wavelength and increased wavelength
(C) original wavelength and decreased wavelength
(D) original wavelength and both increased and decreased wavelengths
Ans: D
56. The characteristic property of a laser beam is
(A) Coherent beam only
(B) Monochromatic beam only
(C) A diverging beam only
(D) Coherent and monochromatic both
Ans: D
57. The transition involving electro magnetic radiation are possible between two energy levels due to
(A) Induced absorption emission only
(B) Spontaneous emission only
(C) Stimulated emission only
(D) All the above
Ans: D
58. For recording an ultra violet spectrum of shorter wavelength
(A) Plane Transmission grating is used
(B) Concave reflection grating is used
(C) Crystal is used
(D) Prism is used
Ans: B
59. When ultra violet light is used for illumination,
(A) the resolving power of a telescope is increased
(B) the resolving power of a telescope is decreased
(C) the resolving power of a microscope is decreased
(D) the resolving power of a microscope is increased
Ans: D
60. Globar filament is a rod made of ________
(A) rare earth oxides
(B) carborundum
(C) copper
(D) semiconductor
Ans: B
61. In IR spectrometer lenses and mirrors are made of---
(A) quartz
(B) glass
(C) mineral salt
(D) calcite
Ans: C
62. A radical is Raman active, if there is a change in -----of the molecule during the application of an electric field
(A) dipole moment
(B) electrical polarizability
(C) bond length
(D) bond angle
Ans: B
63. If a molecule has a centre of symmetry, then Raman active vibrations are ----
(A) IR active
(B) IR inactive
(C) Microwave active
(D) Microwave inactive
Ans: B
64. The quality factor - Q of a laser cavity measure
(A) gain
(B) losses
(C) broadening
(D) population inversion
Ans: B
65. The pumping process is Ruby laser is by
(A) Optical means
(B) Electrical means
(C) Chemical means
(D) Gas dynamic means
Ans: A
66. The role of He atoms in He - Ne laser is to assist in the
(A) pumping process
(B) laser action
(C) laser oscillation
(D) population inversion
Ans: A
67. The dynamo dissipates 20 watt when it supplies a current of 4 ampere through it. The
terminal potential difference is 220V. The e.m.f. produced by the dynamo is
(A) 220 V
(B) 225V
(C) 230 V
(D) 240 V
Ans: B
68. When a material is used in a magnetic field B, a magnetic moment proportional to B but opposite in direction is induced. The material is
(A) Diamagnetic
(B) Paramagnetic
(C) Ferromagnetic
(D) Antimagnetic
Ans: A
69. When two equal and perfectly elastic spheres impinge directly,
(A) their velocities remain unchanged
(B) their velocities are changed
(C) their velocities are interchanged
(D) none of the above
Ans: C
70. You are travelling in a car during a thunderstorm. In order to protect yourself from
lightning would you prefer to
(A) remain in the car
(B) take shelter under a tree
(C) get out and lie flat on the ground
(D) touch the nearest electric pole
Ans: A
71. The resistance of 20 cm long wire is 5 ohms. The wire is stretched to a uniform wire of 40 cm length. The resistance now will be (in ohms)
(A) 5
(B) 10
(C) 20
(D) 200
Ans: C
72. By electrostatic induction
(A) only positive charge can be produced
(B) only negative charge can be produced
(C) any charge can be produced
(D) any charge can be induced
Ans: D
73. Paramagnetism is the property of
(A) paired electrons
(B) filled electronic sub shells
(C) unpaired electrons
(D) vacant electronic subshells
Ans: C
lightning would you prefer to
(A) remain in the car
(B) take shelter under a tree
(C) get out and lie flat on the ground
(D) touch the nearest electric pole
Ans: A
71. The resistance of 20 cm long wire is 5 ohms. The wire is stretched to a uniform wire of 40 cm length. The resistance now will be (in ohms)
(A) 5
(B) 10
(C) 20
(D) 200
Ans: C
72. By electrostatic induction
(A) only positive charge can be produced
(B) only negative charge can be produced
(C) any charge can be produced
(D) any charge can be induced
Ans: D
73. Paramagnetism is the property of
(A) paired electrons
(B) filled electronic sub shells
(C) unpaired electrons
(D) vacant electronic subshells
Ans: C
74. A point source emits sound equally in all directions in a non-absorbing medium. Two points P and Q are at distance of 2m and 3m respectively from the source. The ratio of the intensities of the waves at P and Q is :
1) 9 : 4
2) 2 : 9
3) 9 : 2
4) 4 : 9
Ans: 1
75. A bomb of mass 30 kg at rest explodes into two pieces of masses 18 kg and 12 kg. The velocity of 18 kg mass is 6 ms-1. The kinetic energy of the other mass is :
1) 243 J
2) 486 J
3) 564 J
4) 388 J
Ans: 2
76. A drum of radius R and mass M, rolls down without slipping along an inclined plane of angle θ. The frictional force :
1) converts translational energy to rotational energy
2) dissipates energy as heat
3) decreases the rotational motion
4) decreases the rotational and translational motion
Ans: 1
77. Imagine a new planet having the same density as that of earth but it is 3 times bigger than the earth in size. If the acceleration due to gravity on the surface of earth is g and that on the surface of the new planet is g', then :
1) g' = 3g
2) g' = g/9
3) g' = 9g
4) g' = g/3
Ans: 1
78. Which of the following circular rods, (given radius r and length l) each made of the same material and whose ends are maintained at the same temperature will conduct most heat ?
1) r = 2r0; l = 2l0
2) r = 2r0; l = l0
3) r = r0; l = l0
4) r = r0; l = 2l0
Ans: 2
79. In the reaction 21H + 31H → 42He + 10n, if the binding energies of 21H, 31H and 42He are respectively a, b and c (in MeV), then the energy (in MeV) released in this reaction is :
1) c + a - b
2) c - a - b
3) a + b + c
4) a + b - c
Ans: 2
80. Energy levels A, B and C of a certain atom correspond to increasing values of energy i.e., EA < EB < EC. If λ1, λ2 and λ3 are wavelengths of radiations corresponding to transitions C to B, B to A and C to A respectively, which of the following relations is correct ?
1) λ3 = λ1 + λ2
2) λ3 = (λ1λ2)/(λ1 + λ2)
3) λ1 + λ2 + λ3 = 0
4) λ23 = λ21 + λ22
Ans: 2
81. The work functions for metals A, B and C are respectively 1.92 eV, 2.0 eV and 5 eV. According to Einstein's equation, the metals which will emit photoelectrons for a radiation of wavelength 4100 Å is/are :
1) none
2) A only
3) A and B only
4) all the three metals
Ans: 3
82. The nuclei of which one of the following pairs of nuclei are isotones ?
1) 34Se74, 31Ga71
2) 42Mo92, 40Zr92
3) 38Sr84, 38Sr86
4) 20Ca40, 16S32
Ans: 1
1) 9 : 4
2) 2 : 9
3) 9 : 2
4) 4 : 9
Ans: 1
75. A bomb of mass 30 kg at rest explodes into two pieces of masses 18 kg and 12 kg. The velocity of 18 kg mass is 6 ms-1. The kinetic energy of the other mass is :
1) 243 J
2) 486 J
3) 564 J
4) 388 J
Ans: 2
76. A drum of radius R and mass M, rolls down without slipping along an inclined plane of angle θ. The frictional force :
1) converts translational energy to rotational energy
2) dissipates energy as heat
3) decreases the rotational motion
4) decreases the rotational and translational motion
Ans: 1
77. Imagine a new planet having the same density as that of earth but it is 3 times bigger than the earth in size. If the acceleration due to gravity on the surface of earth is g and that on the surface of the new planet is g', then :
1) g' = 3g
2) g' = g/9
3) g' = 9g
4) g' = g/3
Ans: 1
78. Which of the following circular rods, (given radius r and length l) each made of the same material and whose ends are maintained at the same temperature will conduct most heat ?
1) r = 2r0; l = 2l0
2) r = 2r0; l = l0
3) r = r0; l = l0
4) r = r0; l = 2l0
Ans: 2
79. In the reaction 21H + 31H → 42He + 10n, if the binding energies of 21H, 31H and 42He are respectively a, b and c (in MeV), then the energy (in MeV) released in this reaction is :
1) c + a - b
2) c - a - b
3) a + b + c
4) a + b - c
Ans: 2
80. Energy levels A, B and C of a certain atom correspond to increasing values of energy i.e., EA < EB < EC. If λ1, λ2 and λ3 are wavelengths of radiations corresponding to transitions C to B, B to A and C to A respectively, which of the following relations is correct ?
1) λ3 = λ1 + λ2
2) λ3 = (λ1λ2)/(λ1 + λ2)
3) λ1 + λ2 + λ3 = 0
4) λ23 = λ21 + λ22
Ans: 2
81. The work functions for metals A, B and C are respectively 1.92 eV, 2.0 eV and 5 eV. According to Einstein's equation, the metals which will emit photoelectrons for a radiation of wavelength 4100 Å is/are :
1) none
2) A only
3) A and B only
4) all the three metals
Ans: 3
82. The nuclei of which one of the following pairs of nuclei are isotones ?
1) 34Se74, 31Ga71
2) 42Mo92, 40Zr92
3) 38Sr84, 38Sr86
4) 20Ca40, 16S32
Ans: 1
83. The circular motion of a particle with constant speed is :
1) simple harmonic but not periodic
2) periodic and simple harmonic
3) neither periodic nor simple harmonic
4) periodic but not simple harmonic
Ans: 4
84. A particle executing simple harmonic motion of amplitude 5 cm has maximum speed of 31.4 cm/s. The frequency of its oscillation is :
1) 2 Hz
2) 1.5 Hz
3) 0.5 Hz
4) 1 Hz
Ans: 4
85. The ratio of the dimensions of Planck's constant and that of the moment of inertia is the dimension of :
1) frequency
2) velocity
3) angular momentum
4) time
Ans: 1
86. Which of the following processes is reversible ?
1) Transfer of heat by radiation
2) Electrical heating of a nichrome wire
3) Transfer of heat by conduction
4) Isothermal compression
Ans: 4
87. The temperature of inversion of a thermocouple is 620°C and the neutral temperature is 300°C. what is the temperature of cold junction ?
1) 20°C
2) 120°C
3) -20°C
4) -120°C
Ans: 3
88. A photosensitive metallic surface has work function, hv0. If photons of energy 2hv0 fall on this surface, the electrons come out with a maximum velocity of 4 x 106 m/s. When the photon energy is increased to 5hv0, then maximum velocity of photoelectrons will be :
1) 16 x 106 m/s
2) 8 x 107 m/s
3) 4 x 105 m/s
4) 8 x 106 m/s
Ans: 4
89. Fission of nuclei is possible because the binding energy per nucleon in them :
1) increases with mass number at high mass numbers
2) decreases with mass number at high mass numbers
3) increases with mass number at low mass numbers
4) decreases with mass number at low mass numbers
Ans: 2
90. Application of a forward bias to a p-n junction :
1) increases the number of donors on the n-side
2) increases the electric field in the depletion zone
3) increases the potential difference across the depletion zone
4) widens the depletion zone
Ans: 1
91. The displacement x of a particle varies with time t as x = ae-αt + beβt, where a, b, α and β are positive constants. The velocity of the particle will :
1) go on decreasing with time
2) be independent of α and β
3) drop to zero when α = β
4) go on increasing with time
Ans: 4
92. In any fission process the ratio (mass of fission products/mass of parent nucleus) is :
1) less than 1
2) greater than 1
3) equal to 1
4) depends on the mass of parent nucleus
Ans: 1
93. If a vector 2î + 3ĵ + 8 is perpendicular to the vector 4ĵ - 4î + α , then the value of α is :
1) -2
2) 1/2
3) -(1/2)
4) 2
Ans: 3
94. Zener diode is used for :
1) producing oscillations in an oscillator
2) amplification
3) stabilisation
4) rectification
Ans: 3
1) simple harmonic but not periodic
2) periodic and simple harmonic
3) neither periodic nor simple harmonic
4) periodic but not simple harmonic
Ans: 4
84. A particle executing simple harmonic motion of amplitude 5 cm has maximum speed of 31.4 cm/s. The frequency of its oscillation is :
1) 2 Hz
2) 1.5 Hz
3) 0.5 Hz
4) 1 Hz
Ans: 4
85. The ratio of the dimensions of Planck's constant and that of the moment of inertia is the dimension of :
1) frequency
2) velocity
3) angular momentum
4) time
Ans: 1
86. Which of the following processes is reversible ?
1) Transfer of heat by radiation
2) Electrical heating of a nichrome wire
3) Transfer of heat by conduction
4) Isothermal compression
Ans: 4
87. The temperature of inversion of a thermocouple is 620°C and the neutral temperature is 300°C. what is the temperature of cold junction ?
1) 20°C
2) 120°C
3) -20°C
4) -120°C
Ans: 3
88. A photosensitive metallic surface has work function, hv0. If photons of energy 2hv0 fall on this surface, the electrons come out with a maximum velocity of 4 x 106 m/s. When the photon energy is increased to 5hv0, then maximum velocity of photoelectrons will be :
1) 16 x 106 m/s
2) 8 x 107 m/s
3) 4 x 105 m/s
4) 8 x 106 m/s
Ans: 4
89. Fission of nuclei is possible because the binding energy per nucleon in them :
1) increases with mass number at high mass numbers
2) decreases with mass number at high mass numbers
3) increases with mass number at low mass numbers
4) decreases with mass number at low mass numbers
Ans: 2
90. Application of a forward bias to a p-n junction :
1) increases the number of donors on the n-side
2) increases the electric field in the depletion zone
3) increases the potential difference across the depletion zone
4) widens the depletion zone
Ans: 1
91. The displacement x of a particle varies with time t as x = ae-αt + beβt, where a, b, α and β are positive constants. The velocity of the particle will :
1) go on decreasing with time
2) be independent of α and β
3) drop to zero when α = β
4) go on increasing with time
Ans: 4
92. In any fission process the ratio (mass of fission products/mass of parent nucleus) is :
1) less than 1
2) greater than 1
3) equal to 1
4) depends on the mass of parent nucleus
Ans: 1
93. If a vector 2î + 3ĵ + 8 is perpendicular to the vector 4ĵ - 4î + α , then the value of α is :
1) -2
2) 1/2
3) -(1/2)
4) 2
Ans: 3
94. Zener diode is used for :
1) producing oscillations in an oscillator
2) amplification
3) stabilisation
4) rectification
Ans: 3
95. A stone tied to the end of a string of 1 m long is whirled in a horizontal circle with a constant speed. If the stone makes 22 revolutions in 44 s, what is the magnitude and direction of acceleration of the stone ?
1) (π2/4) ms-2 and direction along the radius towards the centre
2) 2π2 ms-2 and direction along the radius away from centre
3) π2 ms-2 and direction along the radius towards the centre
4) 4π2 ms-2 and direction along the tangent to the circle
Ans: 3
96. If the magnetic dipole moment of an atom of diamagnetic material, paramagnetic material and ferromagnetic material are denoted by µd, µp and µf respectively, then :
1) µd ≠ 0 and µf ≠ 0
2) µp = 0 and µf ≠ 0
3) µd = 0 and µp ≠ 0
4) µd ≠ 0 and µp = 0
Ans: 3
97. In a circuit, L, C and R are connected in series with an alternating voltage source of frequency f. The current leads the voltage by 45°. The value of C is :
1) (1)/(2πf(2πfL + R))
2) (1)/(πf(2πfL + R))
3) (1)/(2πf(2πfL - R))
4) (1)/(πf(2πfL - R))
Ans: 3
98. The angular resolution of a 10 cm diameter telescope at a wavelength of 5000 Å is of the order of :
1) 106 rad
2) 10-4 rad
3) 104 rad
4) 10-6 rad
Ans: 4
99. Two vibrating tuning forks produce progressive waves given by y1 = 4 sin 500 πt and y 2 = 2 sin 506 πt. Number of beats produced per minute is :
1) 360
2) 180
3) 120
4) 30
Ans: 2
100. When a wire of uniform cross-section a, length l and resistance R is bent into a complete circle, resistance between two of diametrically opposite points will be :
1) R/4
2) 2R
3) 4R
4) R/2
Ans: 1
101. When a glass rod is rubbed with a piece of silk cloth,
A) electrons are transferred from silk to glass
B) electrons are transferred from glass to silk
C) protons are transferred from silk to glass
D) protons are transferred from glass to silk
Ans: B
102. What is the diameter of the optical fibres used to carry voice, video and data signals in telecommunication networks ?
A) 6 mm
B) 60 mm
C) 6 µm
D) 60 µm
Ans: D
103. The control rods in a nuclear reactor
(A) absorb neutrons
(B) accelerate neutrons
(C) slowdown neutrons
(D) absorb excess heat produced in the reactor
Ans: A
104. When a particle moves in a circle with a uniform speed
A) its velocity and acceleration are both constant
B) its velocity is constant but the acceleration changes
C) its acceleration is constant but the velocity changes
D) its velocity and acceleration both change
Ans: D
105. Pauli's exclusion principle states that in an atom
A) two electrons can have all the quantum numbers same
B) no two electrons can have all the quantum numbers same
C) particles with Integer and half Integer spin cannot exist in the same state
D) all electrons can have all the quantum numbers same.
Ans: B
106. The critical velocity of a liquid flowing through a tube is
I. directly proportional to coefficient of viscosity
II. inversely proportional to density of the liquid
III. directly proportional to the radius of the tube
IV. inversely proportional to the radius of the tube.
Of these .
A) All are correct
B) I, II and IV are correct
C) I, III & IV are correct
D) II, III & IV are correct
Ans: B
107. The unit of measurement for luminous intensity is
(A) lumen (B) candela (C) lumens/sq.m (D) lumens / watt
Ans: B
1) (π2/4) ms-2 and direction along the radius towards the centre
2) 2π2 ms-2 and direction along the radius away from centre
3) π2 ms-2 and direction along the radius towards the centre
4) 4π2 ms-2 and direction along the tangent to the circle
Ans: 3
96. If the magnetic dipole moment of an atom of diamagnetic material, paramagnetic material and ferromagnetic material are denoted by µd, µp and µf respectively, then :
1) µd ≠ 0 and µf ≠ 0
2) µp = 0 and µf ≠ 0
3) µd = 0 and µp ≠ 0
4) µd ≠ 0 and µp = 0
Ans: 3
97. In a circuit, L, C and R are connected in series with an alternating voltage source of frequency f. The current leads the voltage by 45°. The value of C is :
1) (1)/(2πf(2πfL + R))
2) (1)/(πf(2πfL + R))
3) (1)/(2πf(2πfL - R))
4) (1)/(πf(2πfL - R))
Ans: 3
98. The angular resolution of a 10 cm diameter telescope at a wavelength of 5000 Å is of the order of :
1) 106 rad
2) 10-4 rad
3) 104 rad
4) 10-6 rad
Ans: 4
99. Two vibrating tuning forks produce progressive waves given by y1 = 4 sin 500 πt and y 2 = 2 sin 506 πt. Number of beats produced per minute is :
1) 360
2) 180
3) 120
4) 30
Ans: 2
100. When a wire of uniform cross-section a, length l and resistance R is bent into a complete circle, resistance between two of diametrically opposite points will be :
1) R/4
2) 2R
3) 4R
4) R/2
Ans: 1
101. When a glass rod is rubbed with a piece of silk cloth,
A) electrons are transferred from silk to glass
B) electrons are transferred from glass to silk
C) protons are transferred from silk to glass
D) protons are transferred from glass to silk
Ans: B
102. What is the diameter of the optical fibres used to carry voice, video and data signals in telecommunication networks ?
A) 6 mm
B) 60 mm
C) 6 µm
D) 60 µm
Ans: D
103. The control rods in a nuclear reactor
(A) absorb neutrons
(B) accelerate neutrons
(C) slowdown neutrons
(D) absorb excess heat produced in the reactor
Ans: A
104. When a particle moves in a circle with a uniform speed
A) its velocity and acceleration are both constant
B) its velocity is constant but the acceleration changes
C) its acceleration is constant but the velocity changes
D) its velocity and acceleration both change
Ans: D
105. Pauli's exclusion principle states that in an atom
A) two electrons can have all the quantum numbers same
B) no two electrons can have all the quantum numbers same
C) particles with Integer and half Integer spin cannot exist in the same state
D) all electrons can have all the quantum numbers same.
Ans: B
106. The critical velocity of a liquid flowing through a tube is
I. directly proportional to coefficient of viscosity
II. inversely proportional to density of the liquid
III. directly proportional to the radius of the tube
IV. inversely proportional to the radius of the tube.
Of these .
A) All are correct
B) I, II and IV are correct
C) I, III & IV are correct
D) II, III & IV are correct
Ans: B
107. The unit of measurement for luminous intensity is
(A) lumen (B) candela (C) lumens/sq.m (D) lumens / watt
Ans: B