JEE Main 2026 Apr 6 Shift 1, Chemistry Q5: Calorimetry

JEE Main2026Apr 6, Shift 1Chemistry

Arrange the following isothermal processes in order of the magnitude of the work ( $p$ – $V$ ) involved between states $1$ and $2$ .

A. Expansion in single stage $w_{A}$

B. Expansion in multi stages $w_{B}$

C. Compression in single stage $w_{C}$

D. Compression in multi stages $w_{D}$

A
$∣ w_{B} ∣ > ∣ w_{A} ∣ > ∣ w_{C} ∣ > ∣ w_{D} ∣$
B
$∣ w_{C} ∣ > ∣ w_{D} ∣ > ∣ w_{A} ∣ > ∣ w_{B} ∣$
C
$∣ w_{C} ∣ > ∣ w_{D} ∣ > ∣ w_{B} ∣ > ∣ w_{A} ∣$
D
$∣ w_{B} ∣ > ∣ w_{A} ∣ > ∣ w_{D} ∣ > ∣ w_{C} ∣$

Solution

On a $P$ - $V$ diagram between fixed endpoints $1$ and $2$ , the magnitude of work equals the area under the path.

Expansions (gas does work on surroundings): a single-stage expansion against a low external pressure traces a small rectangle, while a multi-stage (reversible-like) expansion traces a larger area. So $∣ w_{A} ∣ < ∣ w_{B} ∣$ .

Compressions (surroundings do work on gas): a single-stage compression against a high external pressure traces a large rectangle, while multi-stage compression traces a smaller area. So $∣ w_{D} ∣ < ∣ w_{C} ∣$ .

Comparing across categories, the single-stage compression has the largest magnitude and the single-stage expansion the smallest:

$∣ w_{C} ∣ > ∣ w_{D} ∣ > ∣ w_{B} ∣ > ∣ w_{A} ∣$ .

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JEE Main 2026 Apr 6 Shift 1, Chemistry Q5: Calorimetry

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