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

Answer

1

Explanation

`DeltaW_(AB)= PDeltaV = (10)(2-1)= 10 J`
`DeltaW_(BC) = 0`
From first law of thermodynamics
`DeltaQ= DeltW + DeltaU`
`DeltaU =0` (process ABCD is cycle)
`therefore DeltaQ = DeltaW_(AB) + DeltaW_(BC) + DeltaW_(CA)`
`thereforeDeltaW_(CA) = DeltaQ- DeltaW_(AB) - DeltaW_(BC)= 5-10-0 = -5J`