0.08 kg air is heated at constant volume through 5 ° C . The specific heat of air at constant volume is 0.17 kcal / kg ° C and J =4.18 joule / cal . The change in its internal energy is approximately.

Physics · Thermodynamics

JEE Main 2024 — 27 January, Shift 1 — Question 37

0.08 kg air is heated at constant volume through $5^{\circ} \mathrm{C}$ . The specific heat of air at constant volume is $0.17 \mathrm{kcal} / \mathrm{kg}^{\circ} \mathrm{C}$ and $\mathrm{J}=4.18$ joule $/ \mathrm{cal}$ . The change in its internal energy is approximately.

Option A:
318 J
Option B:
298 J
Option C:
284 J
Correct
Option D:
142 J

Answer: C

Step-by-step solution

$\mathrm{Q}=\Delta \mathrm{U}$

as work done is zero [constant volume] $\Delta \mathrm{U}=\mathrm{ms} \Delta \mathrm{T}$

$=0.08 \times(170 \times 4.18) \times 5$

$\simeq 284 \mathrm{~J}$

Answer key and solution verified before publishing.

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Exam: JEE Main 2024
Paper: 27 January, Shift 1
Subject: Physics
Chapter: Thermodynamics
Topic: Calculation of Work, Heat and Internal Energy