$4$ In a sealed $\backslash (10\backslash$mathrm$\{$~m$\}^\{3\}\backslash )$ case, you have placed a large dish of water in close thermal contact with a frictionless piston of ideak gas. If the air inside the case is at a relative humidity of $\backslash (60\backslash \%\backslash )$ at $\backslash (20^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash ),$ how much work can be done by$/$on the piston due to water evaporation? Assume isothermal processes by the piston.