Question

As shown in the figure three p-V diagrams .In which case the work done is minimum.

• A. I
• B. II
• C. III
• D. cannot say

Answer 1

Answer: (C)

III

Work done by a gas is define as Work=change in (Pressure*volume)

or by graph we can define it as Work = area under the curve of pressure and volume graph.

In figure a certain mass of gas traces three path 1,2,3 from state A to the state B.If work done by the gas along the three paths are W1,W2,W3 respectively.

Since the work done by gas = area under the curve of pressure and volume graph. and the area under the graph is more in $I>II>III$

Hence the work done is also in order $W_I>W_{II}>W_{III}$

Hence work done is minimum in III