The molar specific heat at constant pressure of an ideal gas is `(7//2 R)`. The ratio of specific heat at constant pressure to that at constant volume is

Options

A. `7//5`
B. `8//7`
C. `5//7`
D. `9//7`

Answer

A

Explanation

Molar specific heat at contant pressure,
`C_(p)=(7)/(2)R`
Mayer's relation can be written as , `C_(p)-C_(p)=R`
`rArr C_(v)=C_(p)-R`
`=(7)/(2)R-R=(5)/(2)R`
Hence , required ratio, `gamma=C_(p)/C_(v)`
`(((7)/(2))R)/(((5)/(2))R)=(7)/(5)`