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

A

Explanation

For cyclic process. Total work done =`W_(AB)+W_(BC)+W_(CA)`
`DeltaW_(AB)=PDeltaV=10(2-1)=10J` and `Delta W_(BC) = 0`
(as `V` = constant)
From `FLOT` `DeltaQ=DeltaU+DeltaW`
`DeltaU=0` (process `ABCA` is cyclic)
`implies DeltaQ=DeltaW_(AB)+DeltaW_(BC)+DeltaW_(CA)`
`implies 5+10+0+DeltaW_(CA)impliesDeltaW_(CA)=-5J`.