Question

In given figure, when a thermodynamic system is taken from state `A` to state `B` via path `ACB,100` cal of heat given to the system and `60cal` work is done by the gas. Along the path `ADB`, the work done by the gas is `20cal`. Find the heat flowing into the system in this case?

Answer 1

Correct Answer - `60 cal`
`dQ = dU +dW`
`dU_(1) = dQ_(1) - dW_(1) = 100 - 60 = 40 cal`
`dU_(2) = dQ_(2) - dW_(2) = dQ_(2) - 20 cal`
`dU_(1) = dU_(2)`
`40 = dQ_(2) - 20, dQ_(2) = 60cal`