Work done in Isothermal Process :

Consider 1gm mole of an ideal gas enclosed in a cylinder with perfectly conducting walls and fitted with a perfectly frictionless and conducting piston.

If A is the area of cross section of piston, then force exerted by gas on the piston is :

F = P.A

F = P.A

dW = F.dx

or dW = P.(A.dx)

or dW = P.dV

Therefore , the total work done by gas in expansion from V1 to V2 is given by :

& total amount of heat absorbed can be calculated as :-

Here Q is the amount of heat absorbed in calories.