Q.

Under isothermal condition, the pressure of a gas is given by P=aV-3, where a is a constant and V is the volume of the gas. The bulk modulus at constant temperature is equal to                    [2023]

1 P2  
2 3P  
3 2P  
4 P  

Ans.

(2)

Bulk modulus,  B=-dPdvv

Given: Pv3=a

Differentiating with respect to pressure:

v3+3Pv2dvdP=0v=-3PdvdP

Hence, dPvdv=-3P

B=-(dPvdv)=-(-3P)=3P