JEE PYQ: Thermodynamics Question 12
Question 12 - 2021 (26 Feb Shift 2)
1 mole of rigid diatomic gas performs a work of $\frac{Q}{5}$ when heat Q is supplied to it. The molar heat capacity of the gas during this transformation is $\frac{xR}{8}$. The value of $x$ is __________.
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Answer: 25
Solution
From thermodynamics law:
$\Delta Q = \Delta U + \Delta W$ …(1)
$Q = nC_v\Delta T + \frac{Q}{5}$
$Q - \frac{Q}{5} = 1 \times \frac{5}{2}R \times \Delta T$
$Q = \frac{25}{8}R\Delta T$ …(2), so $Q = nc\Delta T$
$c = \frac{25}{8}R$, given $C = \frac{xR}{8}$
$x = 25$
BETA
