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