A diatomic gas is used in car not heat engine having efficiency 80% . Find the ratio of initial volume to final volume of gas during adiabatic expansion.

Options

A. `(1/5)^(3/2)`
B. `(1/3)^(5/2)`
C. `(1/5)^(5/2)`
D. `(1/5)^(2/5)`

Answer

C

Explanation

`eta = 1 - T_(2)/T_(1)`
`0.8 = 1 -T_(2)/T_(1)`
`T_(2)/T_(1) = 0.2`
`T_(2)V_(2)^(lambda-1) = T_(1)V_(1)^(lambda-1)`
`V_(1)/V_(2) = (1/5)^(5/2)`