Four moles of an ideal gas is initially in state `A` having pressure ` 2 xx 10^(5) N//m^(2)` and temperature ` 200 K` . Keeping the pressure constant the gas is taken to state `B` at temperature of `400K`. The gas is then taken to a state `C` in such a way that its temperature increases and volume decreases. Also from `B` to `C` , the magnitude of `dT//dV` increases. The volume of gas at state `C` is eqaul to its volume at statem `A`. Now gas is taken to initial state `A` keeping volume constant. A total `1000 J` of heat is withdrawn from the sample of the cyclic process . Take `R=8.3 J// K// mol`.
The work done in path `B` to `C` is

Options

A. `1000 J`
B. `-1000 J`
C. `-7640 J`
D. `5640 J`

Answer

C

Explanation

In cyclic process
` DeltaU=0`
`W_(AB)+W_(BC)+W_(CA)=-1000J`
`4.R+W_(BC)+0=-1000J`
`W_(BC)=-7640 J`