Volume versus temperature graph of two moles of helium gas is as shown in figure. The ratio of heat absorbed and the work done by the gas in process `1-2` is

Options

A. `3`
B. `5//2`
C. `5//3`
D. `7//2`

Answer

B

Explanation

`V-T` graph is a straight line passing through origin.Hence, `VpropT` or `P` =constant
`:. Dq=nC_(p)dT and dU=nC_(v)dT`
`:. dW=dQ-dU=n(C_(p)-C_(v))dT`
`:. (dQ)/(dW)=(nC_(p)dT)/(n(C_(p)-C_(v))dT)=(C_(p))/(C_(p)-C_(v))=(1)/(-1(C_(v))/(C_(p)))`
`(C_(v))/(C_(P))=(3)/(5)`
`:. (dQ)/(dW)=(1)/(1-3//5)=(5)/(2)`.