A gas at $10$ bar and volume $0\mathrm{.}05m3$ is contained in a piston$-$cylinder device. If the gas undergoes following processes in a reversible manner, calculate the work done by the gas in each of the processes.

a$.$ Isobaric expansion to a final volume of $0\mathrm{.}2m^3$

b$.$ Isothermal expansion to a final volume of $0\mathrm{.}1m^3$

c$.$ Polytrophic expansion to a final volume of $0\mathrm{.}06m^3$ where, the Polytrophic index $n=3$