Q: In an isothermal process on an ideal gas, the pressure increases by 0.5%. The volume decreases by about

(a) 0.25 %

(b) 0.50 %

(b) 0.7 %

(d) 1 %

Ans: (b)

Sol: $P’ = P + \frac{0.5 P}{100}$

Since , $\large P V = P’ V’ $

$\large P V = P (1 + \frac{0.5}{100}) V’ $

$\large \frac{V’}{V} = (1 + \frac{0.5}{100})^{-1} $

$\large \frac{V’}{V} = (1 – \frac{0.5}{100}) $

$\large (\frac{V’}{V} -1 )\times 100 = – \frac{0.5}{100}\times 100 $

= -0.5 %