A gas undergoes the following reversible non-flow processes during its initial pressure of 15 bar and volume \(1 \mathrm{~m}^{3} / \mathrm{kg}\) to final pressure of 6 bar and volume \(2 \mathrm{~m}^{3} / \mathrm{kg}\).

(a) Constant volume followed by constant pressure.

(b) Constant pressure followed by constant volume.

(c) Polytropic process, \(p v^{1.3}=c\).

Calculate the work done by the gas during each process.