Select the correct alternatives for an ideal gas :

Options

A. The change in internal energy un a constant pressure process from temperature `T_(1) to T_(2)` is equal to `nC_(v)(T_(2)-T_(1)), where C_(v)` is the molar specific heat at constant volume and n the number of moles of the gas.
B. The change in internal energy of the gas and the work done by the gas are equal in magnitude in an adiabatic process.
C. The internal energy dose not change in an isothermal process.
D. No heat is added or removed in an asiabatic process.

Answer

A, B, C, D

Explanation

(a) `DeltaU=Q-W=Nc_(P)DeltaT-PDeltaV`
`=Nc_(P)DeltaT-nRDeltaT=n(C_(P)-R)DeltaT` ltBRgt `=Nc_(V)DeltaT=nC_(V)(T_(2)-T_(1))`
(b) ` DeltaQ=DeltaU+DeltaW`
But `DeltaQ=0` for adiabatic process, hence
`DeltaU=-DeltaW , or,|DeltaU|=|DeltaW|`
(c) `Delta U=nC_(V)DeltaT=0 , ( :.DeltaT=0)`
(d) `DeltaQ=0` (in adiabatic change)