the average height at which a molecule makes its last collision before crossing
the plane is

2λ.

3

The average energy of helium molecules is ¯E = 2.89 ×10⁻²¹J. Calculate their average speed (¯v).

Define first order phase transition. Derive the Clausius-Clapeyron equation. Plot
(a) entropy, and (b) Gibbs function as a function of temperature for a first order phase transition.

Consider a classical linear oscillator with

ε = p²/2m + bx²

^{where b is a constant. Assuming that the oscillator is in thermal equilibrium with a
heat reservoir at temperature T, calculate (i) the mean kinetic energy, (ii) the mean
potential energy for an assembly of N such oscillators.}

Write principal merits of a Pt-resistance thermometer.

Represent the following processes on the p-V diagrams: i) isobaric, ii) isochoric,
iii) isothermal, iv) cyclic.

Define thermodynamic probability (W) of the macrostate. Establish the relation
between entropy (S) and W.