Thermodynamic and Statistical Physics (CSIR Physical Sciences): Questions 38 - 40 of 56

Get 1 year subscription: Access detailed explanations (illustrated with images and videos) to 401 questions. Access all new questions we will add tracking exam-pattern and syllabus changes. View Sample Explanation or View Features.

Rs. 300.00 or

Question number: 38

» Thermodynamic and Statistical Physics » Ferromagnetism

Appeared in Year: 2012

MCQ▾

Question

The magnetization M of a ferro-magnet, as a function of the temperature T and the magnetic field H, is described by the equation M=tanh(TCTM+HT) . In these units, the zero – field magnetic susceptibility in terms of M(0)=M(H=0) is given by, (June)

Choices

Choice (4) Response

a.

1M2(0)TTC(1M2(0))

b.

1M2(0)T

c.

1M2(0)TTC

d.

1M2(0)T+TC

Question number: 39

» Thermodynamic and Statistical Physics » Ising Model

Appeared in Year: 2012

MCQ▾

Question

Consider a one – dimensional Ising model with N spins, at very low temperature when almost all the spins are aligned parallel to each other. There will be a few spin flips with each flip costing an energy 2J . In a configuration with r spin flips, the energy of the system is E=NJ+2rJ and the number of configuration is NCr ; r varies from 0 to N. The partition function is – (December)

Choices

Choice (4) Response

a.

eNJkBT

b.

(sinhJkBT)N

c.

(coshJekBT)N

d.

(JkBT)N

Question number: 40

» Thermodynamic and Statistical Physics » Blackbody Radiation

Appeared in Year: 2012

MCQ▾

Question

Consider black body radiation contained in a cavity whose walls are at temperature T. The radiation is in equilibrium with the walls of the cavity. If the temperature of the walls is increased to 2T and the radiation is allowed to come to equilibrium at the new temperature, the entropy of the radiation increases by a factor of (June)

Choices

Choice (4) Response

a.

8

b.

16

c.

4

d.

2

Sign In