Question

The isothermal Bulk modulus of an ideal gas at pressure $P$ is

• A. $P$
• B. $\gamma P$
• C. $P/2$
• D. $P/\gamma$

Answer 1

Answer: (A)

Bulk modulus $=\frac{\text{ Volumestress }}{\text{ Volume strain }}$
$=\frac{dP}{-(dV/V)}=-V\frac{dP}{dV}$
${\left(\frac{dP}{dV}\right)}_{\text{is }}=\left(-\frac{P}{V}\right)$
$\Rightarrow B=(-V)\left(\frac{-P}{V}\right)=P$