## 11 July 2011

### Objective Type Questions - Thermodynamics & Statistical Physics

1. The first law of thermodynamics is conservation of ...................

a) Momentum

b) Energy

c) Both a and b

d) None of these

2. The change in entropy is .............

a) Positive in a reversible change

b) Negative in an irreversible change

c) Positive in an irreversible change

d) Negative in a reversible change

3. Change in entropy depends .........

a) Only on the transfer of heat

b) Only on change of temperature

c) On transfer of mass

d) On the thermodynamic state

4. The Gibb's function G in thermodynamics is defined as G = H-TS. In an isothermal, isobaric, reversible process, G .............

a) Remains constant but not zero

b) Varies linearly

c) Varies non linearly

d) is zero

5. When applied to solar radiation, Planck's law reduces to Wien's law in the ............

a) Ultraviolet region

b) Microwave region

c) Infrared region

d) Visible region

6. According to Maxwell's law of distribution of velocities of molecules, the most probable velocity is ........

a) Greater than the mean velocity

b) Equal to the mean velocity

c) Equal to root mean square velocity

d) Less than the root mean square velocity

7.In a micro canonical ensemble, a system A of fixed volume is in contact with a large reservoir B. Then .......

a) A can exchange only energy with B

b)  A can exchange only particles with B

c) A can exchange neither energy nor particles with B

d) A can exchange both energy and particles with B

8. In a canonical ensemble, a system A of fixed volume is in contact with a large reservoir B. Then .......

a) A can exchange only energy with B

b)  A can exchange only particles with B

c) A can exchange neither energy nor particles with B

d) A can exchange both energy and particles with B

9. In a grand canonical ensemble, a system A of fixed volume is in contact with a large reservoir B. Then .......

a) A can exchange only energy with B

b)  A can exchange only particles with B

c) A can exchange neither energy nor particles with B

d) A can exchange both energy and particles with B

10. In case of Bose - Einstein condensation ..................

a) Number of particles increase in lower energy levels at low temperatures and high pressures

b) Number of particles decreases in lower energy levels at low temperatures and high pressures

c) Number of particles increase in lower energy levels at high temperatures and low pressures

d) Number of particles decreases in lower energy levels at high temperatures and low pressures

11. The quantum statistics reduces to classical statistics under the following condition ..............

a) ρ λ3 ≈ 1

b)ρ λ3 >> 1

c) ρ λ3 << 1

d) ρ = 0

12. According to Debye's theory of specific heat at high temperature specific heat is proportional to .......

a)

b) T2

c) T3

d) Independent of T

13. According to Debye's theory of specific heat at low temperature specific heat is proportional to .......

a)

b) T2

c) T3

d) Independent of T

14. Specific heat of metals can be expressed as .................

a) T3

b) AT + BT2

c) AT2 + BT3

d) AT + BT3