An ideal gas is taken through the cycle `A to B to C to A` as shown in the figure . If the net heat supplied to the gas in the cycles is 5J. The magnitude of word done during the process `C to A` is

Options

A. 5 J
B. 10 J
C. 15 J
D. 20 J

Explanation

An ideal gas is taken through the cycle `A to B to C to A` as shown in the figure.

From the graph,
`W_(AB)=P times dV`
`=10 times (2-1) =10J`
Similarly,
`W_(BC)=P times (0)=0J`
According to the first law of thermodynamics
`DeltaQ=DeltaU+W`
Here `Delta U=0`
`thereforeQ=W`
`5=W_(AB)+W_(BC)+W_(CA)`
`W_(CA)=5-W_(AB)-W_(BC)=5-10=0`
`W_(CA)=-5J`
`therefore|W_(CA)|=5J`
Hence, the magnitude of word done during the process `C to A` is 5J.