Graphically show the total work done in an expansion when the state of an ideal gas is changed reversibly and isothermally from (p_(i), V_(i) ) to (P_(f) , V_(f) ). With the help of a pV plot compare the work done in the above case with that carried out against a constant external pressure p_f.

Graphically show the total work done in an expansion when the state of

1.	Graphically show the total work done in an expansion when the state of an ideal gas is changed reversibly and isothermally from (p_(i), V_(i) ) to (P_(f) , V_(f) ). With the help of a pV plot compare the work done in the above case with that carried out against a constant external pressure p_f.
Answer» Solution :(i) TOTAL work done in an expansion when the state of an IDEAL gas is changed reversibly and isothermally p from `(p_(i) , V_(i) )` to `(p_(F) , V_(f) )`. Reversible work is represented by the combined areas ABC and BC `V_(i) V_(f)`. ii) Work against constant PRESSURE, `p_f` is represented by the area `BCV_(i) V_(f)`. Work (i) `gt` work (ii).