JEE Main 2025 Jan 22 Shift 2, Physics Q19: Laws of Thermodynamics

JEE Main2025Jan 22, Shift 2Physics

Given are statements for certain thermodynamic variables,

(A) Internal energy, volume (V) and mass (M) are extensive variables.

(B) Pressure (P), temperature (T) and density ( $ρ$ ) are intensive variables.

(D) Mass (M), temperature (T) and internal energy are extensive variables.

Choose the correct answer from the points given below :

Solution

Extensive variables depend on the size (amount) of the system; intensive variables do not.

Extensive: internal energy ( $U$ ), volume ( $V$ ), mass ( $M$ ), number of moles ( $n$ ), entropy ( $S$ ).

Intensive: pressure ( $P$ ), temperature ( $T$ ), density ( $ρ$ ), molar quantities, chemical potential.

(A) Correctly lists $U$ , $V$ , $M$ as extensive: TRUE.

(B) Correctly lists $P$ , $T$ , $ρ$ as intensive: TRUE.

(D) Lists $T$ as extensive: FALSE, since $T$ is intensive.

$∴$ Only (A) and (B) are correct.

Concept behind this question

Concept-wise practice with instant solutions on Fundamenthol.