Graphically shoe 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 pressure `p_(f)`.

Explanation

(i) Area AB` V_(i) V_(f)` represents total work done for reversible isothermal expansion from `(p_(i), V_(i))` to `p_(f)V_(f)`
Area `CBV_(i)V_(f)` represents work done against constant pressure, `p_(f)`
Work (i) is larger than work (ii)