Question

In cyclic process, work done by the process is:

• A. Independent of heat given to the system
• B. More than the heat given to system
• C. Equal to heat given to the system
• D. zero

Answer 1

Answer: (C)

In a cyclic process, system returns to its initial state.
If an amount of heat $Q$ is given to a system a part of it will be used in increasing the internal energy $(\Delta U)$ of the system and the rest is doing work $(W)$ by the system.
Therefore, $Q=\Delta U+W$ (first law of thermodynamics)
The internal energy of the system does not change in a cyclic process $(\Delta U=0)$ because it is a function of only the state of the system.
$\therefore Q=W$
Hence, in a cyclic process, the heat given to a system equal the net work done by the system.