The coefficient of viscosity of helium at 27°C is 2 x poise. If the gas molecules have mass 6·67 x 10^-27 kg and move with average speed 1·26 x 10^3 calculate the diameter of a helium molecule.

The efficiency of a Carnot engine operating between temperatures T1 and T2 is 1/6. If the temperature of the sink is lowered by 62°C, its efficiency doubles. Calculate the temperatures of the source and sink.

A certain mass of an ideal gas at 27°C and 8 atm pressure is expanded suddenly to four times its initial volume. Calculate the final pressure as well as temperature of the gas. Take y =1·5.

The spectral energy curve of the moon shows maxima at 470 nm and 14 Mm. Calculate the corresponding temperatures. What conclusions can you draw from this data? Take b 2·892 x m-K.

One mole of an ideal gas is made to undergo a quasi-static adiabatic change. The pressure and temperature of the gas are related through T^y constant. Use this result to obtain an expression for adiabatic lapse rate.

The work done by hydrostatic pressure is defined as W integral p dV.(limits V1 to V2) If n moles of an ideal gas are made VI to undergo isothermal process, calculate the work done.

For two (or more) phases of one-component system to exist in equilibrium, the specific Gibbs potential must be equal. Use this fact to derive Clausius -Clapeyron equation and discuss why food cooks more efficiently in a pressure cooker.

'What is Joule -Thomson effect? Discuss qualitatively, how it is used to produce low temperatures.

What do you understand by the term Transport Phenomena Define coefficient of viscosity. Assume that

each molecule makes its last collision at two-third mean free path above or below an imaginary surface and

the number of particles crossing this plane from either side per unit area per second is 1/4 nv.

Obtain an expression for n. Discuss its pressure and temperature dependence.

What is Brownian motion Discuss its characteristics. For one-dimensional Brownian motion, show that diffusion coefficient is connected to displacement s of a particle in time t through the relation D

Define entropy. Show that the change in the entropy during mixing of two gases is given by

ASmix R ln x1-n2 R ln x2 where x1 and x2 are the mole fractions while n1 and n2 are number of moles of the two gases.

Show that Fermi energy at absolute zero temperature is given by

EF= h^2/2m

What is Gibbs paradox? Derive Sakur -Tetrode equation starting from the expression for thermodynamic probability. Show that it is free from Gibbs paradox. Assume that N-particle partition function is given by

ZN V^N