# Statistical Mechanics

1. Apr 16, 2009

### mkbh_10

I have my main UG exam on Sat & i dnt have answer to these questions . Help me out

Q. Distinguish b/w degenerate energy level & a degenerate gas ?

Ans : Degenrate level : A single energy level can be degenerate with another energy level , no difference b/w their energies . Degenerate gas : All particles occupy a single level at a particular temp. for a fermi gas at T=ok gas is completely degenerate , A BE gas show strong degeneracy at T < To .

Q. Which feature of classical statistical is responsible for Gibbs paradox ?

Ans : Entropy

Q. Why can't gravitational potential energy be asssociated with law of equipartition of energy ?

Ans : As it is of quantized character . More explanation needed

Q. A bose gas, fermi gas , classical gas are at same temp ,pressure & hve same no. of molecules . Which one wud hve least volume , largest volume . Give reason

Q.What kind of energy is fermi energy ?

Q. How is Sahas ionisation formula used to estimate stellar temp ?

Q.Explain the principle of detailed balance in lasers ?

Q.Why the chemical potential of a photon gas is zero ?

Q.Why is that electrons are not ejected out spontaneously from the metal inspite of having tremendous zero point pressure ?

Q.Significance of partition function ?

Q.Write the expression for pressure exerted by radiation for 1. Normal radiation ,2. diffuse radiation in terms of energy density

Q. Calculate the mean no. of photons per unit volume at a temp of 300k ?

2. Apr 16, 2009

### guruji

Q. Distinguish b/w degenerate energy level & a degenerate gas ?

ANS: Degenerate level: the energy levels that have more than one energy states with
same energy are known as degenerate energy level.

whereas the gas which shows departure from the ideal gas behaviour
are known as degenerate gas.

3. Apr 16, 2009

### guruji

Q. Distinguish b/w degenerate energy level & a degenerate gas ?

ANS: Degenerate level: the energy levels that have more than one energy states with
same energy are known as degenerate energy level.

whereas the gas which shows departure from the ideal gas behaviour
are known as degenerate gas.