5 moles of unknown gas is heated at constant volume from 10 ° C to 20 ° C . The molar specific heat at constant pressure c p = 8\, cal/mol. ° C and R = 8.36\, J/mol. ° C . The change in internal energy of the gas is calorie.

Physics · Thermodynamics

JEE Main 2026 — 2 April, Evening Shift — Question 20

5 moles of unknown gas is heated at constant volume from $10^\circ\mathrm{C}$ to $20^\circ\mathrm{C}$ . The molar specific heat at constant pressure $c_p = 8\,\mathrm{cal/mol.^\circ C}$ and $R = 8.36\,\mathrm{J/mol.^\circ C}$ . The change in internal energy of the gas is ______ calorie.

Answer: 300

Numerical answer — enter this value.

Step-by-step solution

$c_v = c_p - R = 8 - 2 = 6\,\mathrm{cal/mol.^\circ C}$ (since R≈2 cal/mol.K), $\Delta U = n c_v \Delta T = 5\times6\times10 = 300\,\mathrm{cal}$

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Exam: JEE Main 2026
Paper: 2 April, Evening Shift
Subject: Physics
Chapter: Thermodynamics
Topic: First Law of Thermodynamics

Gas 'A' undergoes change from state ' X ' to state ' Y '. In this process, the heat absorbed and work done by the gas is 10 J and 18 J…

Answer: 300

Step-by-step solution

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