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

Answer

A

Explanation

a. `dU = 0`
There fore by the first law of thermodyamics
`dQ_(Cyclic) = dW_(Cyclic)`
Since `B rarr C` is an isochoric porcess
`implies dW_(a rarrC) = 0`
`implies 5 = dW_(A rarr B) + dW_(a rarr C) + dW_(C rarr A)`
`implies 5 = 10 (2 - 1) + 0 + dW_(C rarr A)`
`dW_(C rarr A) = - 5 J`