Question

The initial state of a certain gas is (P_i, V_i, T_i). It undergoes expansion till its volume becomes V_f. Consider the following two cases:

1. the expansion takes place at constant temperature.
2. the expansion takes place at constant pressure.

Plot the P-V diagram for each case. In which of the two cases, is the work done by the gas more?

Answer 1

The situation is shown in the given P-V graph, where variation is shown for each process.

It is clear from the graph that Process 1 is isobaric and Process 2 is isothermal.

Since the work done is equal to the area under the P-V curve. Here, the area under the P-V curve 1 is more. So, work done is more when the gas expands in the isobaric process as in comparison to gas expands in isothermal.