First Law- Work Done In Different Thermodynamic Processes

2019:

In a cyclic process, the net heat absorbed or rejected is zero. Therefore, the work done is not necessarily zero.

2018:

In an isothermal process, the work done is given by $\text{W} = \int_{V_1}^{V} p\ dV = \int_{V_1}^{V_2} \frac{nRT}{V} dV = nRT \ln \left( \frac{V_2}{V_1} \right)$. Since $V_1 \neq V_2$, the work done is not zero.

2017:

The work done in a cyclic process is given by $\text{W} = \oint p\ dV$. The area enclosed by the curve is $\frac{\pi}{2}\ R\ T$. Therefore, the work done is $\oint p\ dV$.