An ideal gas is taken through the cycle `AtoBtoCtoA,` as shown in the figure, If the net heat supplied to the gas in the cycle is 5J, the work done by the gas in the process CtoA is

Options

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

Answer

C

Explanation

`DeltaQ_(cyclic)=5J`
`DeltaW_(cyclic)=DeltaW_(AB)+DeltaW_(BC)+DeltaW_(CA)`
`=10(2-1)+0+DeltaW_(CA)=20+DeltaW_(CA)`
In cyclic process,
`DeltaW_(cyclic)=DeltaQ_(cyclic)`
`20+DeltaW_(CA)=5`
`DeltaW_(CA)=-15J`