A monoatomic gas expands at constant pressure on heating. The percentage of heat supplied that increases the internal energy of the gas and that is involved in the expansion is :
Answer & explanation
Correct answer: option 3
Fraction of energy supplied for increment in internal energy = \(\frac{1}{\gamma}\)
= \(\frac{3}{5}\) ... [as \(\gamma = \frac{5}{3}\) for monoatomic gas]
Therefore, percentage energy = \(\frac{30}{5}\) = 60%
Fraction of energy supplied for external work done = \(1 - \frac{1}{\gamma} = \frac{\gamma - 1}{\gamma}\)
= \(\frac{\frac{5}{3} - 1}{\frac{5}{3}} = \frac{2}{5}\)
\(\Rightarrow \text { Percentage energy : } = \frac{2}{5}*100% = 40 %\)