A monatomic gas expands at constant pressure on heating. The percentage of heat supplied that increases the internal energy of the gas and that is involed in the expansion is

Options

A. 0.3
B. 0.4
C. 0.5
D. 0.6

Answer

D

Explanation

From first law of thermodynamics, dQ = dU + dW
`(dU)/(dQ)` is the part of heat supplied to the gas, that is used for increasing the internal energy
and `(dU)/(dQ)=(nC_(V)dT)/(nC_(P)dT)=C_(V)/C_(P)=1/gamma`
But for a monoatomic gas, `gamma=C_(P)/C_(V)=5/3`
`therefore(dU)/(dQ)=1/(5//3)=3/5`
`thereforedU=(3/5)dQ`
`therefore` Percentage of heat used for increasing the internal enrgy = `3/5xx100=60%`