A gas is initially at a pressure of 100 kPa and its volume is `2.0m^3`. Its pressure is kept constant and the volume is changes from `2.0m^3` to `2.5m^3`. Its volume is now kept constant and the pressure is increased from 100 kPa to 200 kPa. The gas is brought back to its initial state, the pressure verying linearly with its volume. Whether the heat is supplied to or extracted from the gas in the complete cycle?

Explanation

First draw `P-V`
`DeltaW_(cyclic)=-(1)/(2)(200-100)xx10^3xx(2.5-2.0)`
`=-25000J`
In the cyclic process
`DeltaQ=DeltaW=-25000J`
`-ve` sign shows that heat is extracted.