JEE Main 2021 · PhysicsMultiple choiceSingle correctEasyConceptual

JEE Main 18 March 2021, Shift 2, Physics Q9

Question 9 of 90 in this shift, Physics question 9 of 30, Section A.

For an adiabatic expansion of an ideal gas, the fractional change in its pressure is equal to (where

\gamma

is the ratio of specific heats) :

(1) $-\gamma\,\frac{dV}{V}$ Official answer
(2) $-\gamma\,\frac{V}{dV}$
(3) $-\frac{1}{\gamma}\,\frac{dV}{V}$
(4) $\frac{dV}{V}$

Official answer

Option 1

NTA final key.

Chapter: Thermodynamics
Topic: Thermodynamic Processes
Idea tested: Adiabatic Process Analysis

Same idea in other shifts

Asked 16× in all

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2 Apr 2025, Shift 1 · Q31In an adiabatic process, which of the following statements is true ?EasySingle correct
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8 Apr 2025, Shift 2 · Q33A monoatomic gas having $\gamma = \frac{5}{3}$ is stored in a thermally insulated container and the gas is suddenly compressed to…EasySingle correct
4 Apr 2024, Shift 2 · Q39A sample of gas at temperature $T$ is adiabatically expanded to double its volume. Adiabatic constant for the gas is $\gamma = 3/2$ . The…MediumSingle correct
9 Apr 2024, Shift 1 · Q38A sample of $1$ mole gas at temperature T is adiabatically expanded to double its volume. If adiabatic constant for the gas is…MediumSingle correct
9 Apr 2024, Shift 1 · Q39The volume of an ideal gas ( $\gamma=1.5$ ) is changed adiabatically from $5$ litres to $4$ litres. The ratio of initial pressure to final…EasySingle correct
10 Apr 2023, Shift 1 · Q33Consider two containers A and B containing monoatomic gases at the same Pressure (P), Volume (V) and Temperature (T). The gas in A is…MediumSingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.