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
If the piston is displaced outward through small displacement dx, then small amount of work done:
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.