Question

The volume of air increases by 5% in its adiabatic expansion. The percentage decrease in its pressure will be –

• A. 5%
• B. 6%
• C. 7%
• D. 8%

Answer 1

Answer: (C)

7%

Answer 2

$\frac{\Delta P}{\Delta V} = - \gamma\frac{P}{V} \rightarrow Air \rightarrow diatomic$ (g = 1.4)

\ $\frac{\Delta P}{P} = - \gamma\frac{\Delta V}{V} = - 1.4 \times 5 = 7\%$