In a cyclic process shown in the figure an ideal gas is adiabatically taken from `B`to`A`, the work done on the gas during the process `B`to`A` is `30,J` when the gas is taken from `A` to `B` the heat absorbed by the gas is `20 J` Then change in internal energy of the gas in the process `A` to `B` is :

Options

A. `20 J`
B. `-30 J`
C. `50 J`
D. `-10 J`

Answer

B

Explanation

`B rarr A , DeltaQ = 0, 0 =- 30 +DeltaU_(BA)`
`DeltaU_(BA) = 30 J, :. DeltaU_(AB) = - DeltaU_(BA) =- 30 J`