If heat energy Δ Q is supplied to an ideal diatomic gas, the increase in internal energy is Δ U and the amount of work done by the gas is Δ W. The ratio Δ W: Δ U: Δ Q is (a) 2: 3: 5 (b) 2: 5: 7 (c) 7: 5: 9 (d) 1: 2: 5

Answer: (b). Heat is supplied at constant pressure: Δ Q = nCpΔ T = 7/2nRΔ T for a diatomic gas. Δ U = nCvΔ T = 5/2nRΔ T, Δ W = nRΔ T Δ W: Δ U: Δ Q = 1: 5/2: 7/2 = 2: 5: 7 So the answer is (b) 2: 5: 7.

If heat energy Δ Q is supplied to an ideal diatomic gas, the increase… | MHT CET 2024 (16 May, Shift 1)

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Heat, Work & First Law of Thermodynamics

If heat energy $\Delta Q$ is supplied to an ideal diatomic gas, the increase in internal energy is $\Delta U$ and the amount of work done by the gas is $\Delta W$ . The ratio $\Delta W : \Delta U : \Delta Q$ is

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Answer: (b)

Heat is supplied at constant pressure: $\Delta Q = nC_p\Delta T = \frac{7}{2}nR\Delta T$ for a diatomic gas.
$\Delta U = nC_v\Delta T = \frac{5}{2}nR\Delta T$ , $\Delta W = nR\Delta T$
$\Delta W : \Delta U : \Delta Q = 1 : \frac{5}{2} : \frac{7}{2} = 2 : 5 : 7$
So the answer is (b) 2 : 5 : 7.

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Heat, Work & First Law of Thermodynamics question from MHT CET 2024 (16 May, Shift 1)

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