## PHYSICS- PAGE 6

1. The pair having the same dimension is :

1) velocity , angular velocity

2) Work, Torque

3) Angular momentum , work

4) Angular momentum, Linear momentum

Ans: 2

2. Choose the correct statement for cyclic group :

1) Group of order two may or may not be cyclic.

2) Group of order three is always a cyclic group.

3) Group of order four is always a cyclic group.

4) Group of order four is never a cyclic group.

Ans: 2

3. The group formed by three cube roots of unity is :

1) Only Non Abelian

2) Non Abelian and non cyclic

3) Abelian and non cyclic

4) Abelian and cyclic

Ans: 4

4. If the Lagrangian L is not an explicit function of time , then

1) Hamiltonian H is a constant of motion.

2) Hamiltonian H is not a constant of motion.

3) Angular momentum is a constant of motion.

4) Angular momentum is not a constant of motion.

Ans: 1

5. The invariance of Lagrangian under spatial translations implies the :

1) conservation of linear momentum

2) conservation of angular momentum

3) conservation of energy

4) conservation of parity

Ans: 1

6. Equation E = pc is valid :

1) for an electron as well as a photon

2) for an electron but not for a photon

3) for a photon but not for an electron

4) neither for an electron nor for a photon

Ans: 3

7. A body of mass m moving with velocity v hits another body of same mass moving with same speed v but in the opposite direction and stick to it . The velocity of the compound body after collision is :

1) Zero

2) v/2

3) 2v

4) v/4

Ans: 1

8. Muliplication of two linear operators is :

1) always commutative

2) never commutative

3) not necessarily commutative

4) always a unit operator.

Ans: 3

9. If A and B are self adjoint operators , which of the following statements is not true

1) AB + BA is self adjoint

2) i(AB BA) is self adjoint

3) AB is self adjoint only if AB = BA

4) AB will never be self adjoint

Ans: 4

10. Choose the wrong statement for projection operator :

1) Two projection operator are said to be orthogonal if their product is zero

2) The product of two commutating projection operator is also a projection operator.

3) The sum of two projection operator is always a projector operator

4) Two projection operator are said to be orthogonal if their product is one

Ans:3

11. The probability of finding a simple harmonic oscillator in the classical limit is : [ The oscillator is in its normal state ]

1) 50%

2) 64%

3) 84%

4) 92%

Ans: 3

12. The Clebsch-Gordon coefficients are

1) all real

2) all imaginary

3) real and imaginary both

4) necessarily integer

Ans: 1

13. The first order effect of a time dependent perturbation, varying sinusoidally in time,lead to :

1) absorption of energy only

2) emission of energy only

3) emission and absorption of energy

4) No change of energy

Ans: 3

14. Which of the following experiment is a direct evidence for the quantized nature of energy states in atoms

1) Davisson-Germer experiment

2) Stern-Gerlach experiment

3) Rutherford alpha- scattering experiment

4) Frank-Hertz experiment

Ans: 4

15. A system absorbs 35 J of heat and in the process it does 11 J of work . The system follows another thermodynamics path to same final state from same initial state and does 15 J of work. The heat transferred in the process is :

1) 39 J

2) 31 J

3) 61 J

4) 35 J

Ans: 1

16. The combined form of first and second law of thermodynamics is given by :

1) TdS =dU + PdV

2) dQ = TdS + PdV

3) dU = TdS + dQ

4) TdS = dU PdV

Ans: 1

17. One mole of gas expand isothermally to four times of its initial volume. The change in entropy in terms of gas constant R is :

1) 0.602 R

2) 1.387 R

3) 2.774 R

4) Zero

Ans: 2

18. Choose the correct statement for Enthalpy :

1) Enthalpy has dimension of entropy.

2) For an isobaric process the change in enthalpy is equal to change in its internal energy .

3) Enthalpy remains constant in a reversible isobaric adiabatic process

4) Enthalpy always increases in a reversible isobaric adiabatic process

Ans: 3

19. Enthalpy H, pressure P , internal energy U and volume V have a relation given by :

1) H = U + PV

2) H = U PV

3) P = H UV

4) U = H + P V

Ans: 1

20. For equlibrium of a system , which is in contact with heat reservoir of constant pressure and temperature , the value of Gibbs Energy : 1) is always zero

2) must be minimum

3) must be maximum

4) always increases

Ans: 2

21. Which of the following is not an example of second order phase transitions :

1) Transition of water into ice at constant time

2) Transition of ferromagnetic to a praramagnetic material at curie point.

3) Transition of superconductor into ordinary conductor in the absence of magnetic field.

4) Transition of water into vapour at constant temperature and volume.

Ans: 4

22. Three classical particles are to be distributed in four energy levels . The number of possible ways of distribution are :

1) 81

2) 64

3) 20

4) 12

Ans: 2

23. The significance of Bose - Einstein and Fermi - Dirac statistics becomes negligible at :

1) low temperature

2) low temperature and low pressure

3) high temperature and low pressure

4) low temperature and high pressure

Ans: 3

24. The chemical potential for Fermions (FermiDirac statistics) is :

1) always zero

2) always negative

3) always positive

4) may be negative or positive

Ans: 4

25. For shorter wavelengths, Plank's radiation law reduces to :

1) Wien's Law

2) RayleighJeans Law

3) Kirchhoff's Law

4) Stefan's law

Ans: 1

1) velocity , angular velocity

2) Work, Torque

3) Angular momentum , work

4) Angular momentum, Linear momentum

Ans: 2

2. Choose the correct statement for cyclic group :

1) Group of order two may or may not be cyclic.

2) Group of order three is always a cyclic group.

3) Group of order four is always a cyclic group.

4) Group of order four is never a cyclic group.

Ans: 2

3. The group formed by three cube roots of unity is :

1) Only Non Abelian

2) Non Abelian and non cyclic

3) Abelian and non cyclic

4) Abelian and cyclic

Ans: 4

4. If the Lagrangian L is not an explicit function of time , then

1) Hamiltonian H is a constant of motion.

2) Hamiltonian H is not a constant of motion.

3) Angular momentum is a constant of motion.

4) Angular momentum is not a constant of motion.

Ans: 1

5. The invariance of Lagrangian under spatial translations implies the :

1) conservation of linear momentum

2) conservation of angular momentum

3) conservation of energy

4) conservation of parity

Ans: 1

6. Equation E = pc is valid :

1) for an electron as well as a photon

2) for an electron but not for a photon

3) for a photon but not for an electron

4) neither for an electron nor for a photon

Ans: 3

7. A body of mass m moving with velocity v hits another body of same mass moving with same speed v but in the opposite direction and stick to it . The velocity of the compound body after collision is :

1) Zero

2) v/2

3) 2v

4) v/4

Ans: 1

8. Muliplication of two linear operators is :

1) always commutative

2) never commutative

3) not necessarily commutative

4) always a unit operator.

Ans: 3

9. If A and B are self adjoint operators , which of the following statements is not true

1) AB + BA is self adjoint

2) i(AB BA) is self adjoint

3) AB is self adjoint only if AB = BA

4) AB will never be self adjoint

Ans: 4

10. Choose the wrong statement for projection operator :

1) Two projection operator are said to be orthogonal if their product is zero

2) The product of two commutating projection operator is also a projection operator.

3) The sum of two projection operator is always a projector operator

4) Two projection operator are said to be orthogonal if their product is one

Ans:3

11. The probability of finding a simple harmonic oscillator in the classical limit is : [ The oscillator is in its normal state ]

1) 50%

2) 64%

3) 84%

4) 92%

Ans: 3

12. The Clebsch-Gordon coefficients are

1) all real

2) all imaginary

3) real and imaginary both

4) necessarily integer

Ans: 1

13. The first order effect of a time dependent perturbation, varying sinusoidally in time,lead to :

1) absorption of energy only

2) emission of energy only

3) emission and absorption of energy

4) No change of energy

Ans: 3

14. Which of the following experiment is a direct evidence for the quantized nature of energy states in atoms

1) Davisson-Germer experiment

2) Stern-Gerlach experiment

3) Rutherford alpha- scattering experiment

4) Frank-Hertz experiment

Ans: 4

15. A system absorbs 35 J of heat and in the process it does 11 J of work . The system follows another thermodynamics path to same final state from same initial state and does 15 J of work. The heat transferred in the process is :

1) 39 J

2) 31 J

3) 61 J

4) 35 J

Ans: 1

16. The combined form of first and second law of thermodynamics is given by :

1) TdS =dU + PdV

2) dQ = TdS + PdV

3) dU = TdS + dQ

4) TdS = dU PdV

Ans: 1

17. One mole of gas expand isothermally to four times of its initial volume. The change in entropy in terms of gas constant R is :

1) 0.602 R

2) 1.387 R

3) 2.774 R

4) Zero

Ans: 2

18. Choose the correct statement for Enthalpy :

1) Enthalpy has dimension of entropy.

2) For an isobaric process the change in enthalpy is equal to change in its internal energy .

3) Enthalpy remains constant in a reversible isobaric adiabatic process

4) Enthalpy always increases in a reversible isobaric adiabatic process

Ans: 3

19. Enthalpy H, pressure P , internal energy U and volume V have a relation given by :

1) H = U + PV

2) H = U PV

3) P = H UV

4) U = H + P V

Ans: 1

20. For equlibrium of a system , which is in contact with heat reservoir of constant pressure and temperature , the value of Gibbs Energy : 1) is always zero

2) must be minimum

3) must be maximum

4) always increases

Ans: 2

21. Which of the following is not an example of second order phase transitions :

1) Transition of water into ice at constant time

2) Transition of ferromagnetic to a praramagnetic material at curie point.

3) Transition of superconductor into ordinary conductor in the absence of magnetic field.

4) Transition of water into vapour at constant temperature and volume.

Ans: 4

22. Three classical particles are to be distributed in four energy levels . The number of possible ways of distribution are :

1) 81

2) 64

3) 20

4) 12

Ans: 2

23. The significance of Bose - Einstein and Fermi - Dirac statistics becomes negligible at :

1) low temperature

2) low temperature and low pressure

3) high temperature and low pressure

4) low temperature and high pressure

Ans: 3

24. The chemical potential for Fermions (FermiDirac statistics) is :

1) always zero

2) always negative

3) always positive

4) may be negative or positive

Ans: 4

25. For shorter wavelengths, Plank's radiation law reduces to :

1) Wien's Law

2) RayleighJeans Law

3) Kirchhoff's Law

4) Stefan's law

Ans: 1

26. A semiconductor diode is used to

A:-convert dc to ac

B:-convert ac to dc

C:-increase voltage

D:-decrease voltage

Correct Answer:- Option-B

27. A steady current is flowing in a power line from west to east. The direction of the magnetic field at a point below the power line is towards

A:-east

B:-west

C:-north

D:-south

Correct Answer:- Option-C

28. Polarization of light is a convincing evidence of it's

A:-Longitudinal nature

B:-Transverse nature

C:-Dual nature

D:-Quantum nature

Correct Answer:- Option-B

29. A hollow metal sphere of radius 2 cm is charged such that the potential on it's surface is 5 volts. The potential at the centre of the sphere is

A:-5 volts

B:-zero

C:-same as at a point 2 cm away from the surface

D:-none of these

Correct Answer:- Option-A

30. An athlete completes one round of a circular track of radius 'R' in 40 seconds. His displacement at the end of 2

minutes 20 seconds will be

A:-2 R

B:-zero

C:-2 πR

D:-4 R

Correct Answer:- Option-B

31. At high altitudes, the boiling point of water decreases because

A:-the atmospheric pressure is high

B:-the temperature is low

C:-the atmospheric pressure is low

D:-the temperature is high

Correct Answer:- Option-C

A:-convert dc to ac

B:-convert ac to dc

C:-increase voltage

D:-decrease voltage

Correct Answer:- Option-B

27. A steady current is flowing in a power line from west to east. The direction of the magnetic field at a point below the power line is towards

A:-east

B:-west

C:-north

D:-south

Correct Answer:- Option-C

28. Polarization of light is a convincing evidence of it's

A:-Longitudinal nature

B:-Transverse nature

C:-Dual nature

D:-Quantum nature

Correct Answer:- Option-B

29. A hollow metal sphere of radius 2 cm is charged such that the potential on it's surface is 5 volts. The potential at the centre of the sphere is

A:-5 volts

B:-zero

C:-same as at a point 2 cm away from the surface

D:-none of these

Correct Answer:- Option-A

30. An athlete completes one round of a circular track of radius 'R' in 40 seconds. His displacement at the end of 2

minutes 20 seconds will be

A:-2 R

B:-zero

C:-2 πR

D:-4 R

Correct Answer:- Option-B

31. At high altitudes, the boiling point of water decreases because

A:-the atmospheric pressure is high

B:-the temperature is low

C:-the atmospheric pressure is low

D:-the temperature is high

Correct Answer:- Option-C