P-V diagram of a diatomic gas is a straight line passing through origin. The molar heat capacity of the gas in the process will be

Answer

3

Explanation

`P prop V` since graph is a straight line
`PV^(-1) =` constant
For the process `PV^(x) =` constant, molar heat capacity is given by `C = (R )/((gamma - 1)) + (R )/((1 - x))`
But here `gamma = 1.4` and `x = -1`
So, `C = (R )/((1.4 - 1)) + (R )/((1 + 1)) = 3 R = nR` (Given)
So, `n = 3`