Question

When an ideal gas `(gamma = 5//3)` is heated under constant pressure, what percentage of given heat energy will be utilized in doing external work ?
A. `40%`
B. `30%`
C. `60%`
D. `20%`

Answer 1

Correct Answer - A
a. `(Delta W)/(Delta Q) = (Delta Q - Delta U)/(Delta Q)`
`= (C_(P) - C_(v))/(C_(P)) = 1 - (1)/(gamma) = 1 = (1)/(1 - (5)/(3)) = (2)/(5)`
i.e., percentage energy untilized in doing external work `= (2)/(5) xx 100 = 40 %`