# Work done

One mole of an ideal gas is kept in a rigid vertical cylinder fitted with a light frictionless piston. The space above the piston opens into the atmosphere. The temperature of the gas and the surroundings is $$T$$. What work has to be performed on the piston to increase the volume of the gas by a factor of $$\eta$$? Assume the process to be isothermal and quasistatic.

Universal gas constant$$=R$$.

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