Consider the following statements: A. Zeroth law of thermodynamics gives concept of temperature B. First law of thermodynamics gives concept of internal energy C. In isothermal expansion of ideal gas, ΔQ ≠ ΔW D. Product of intensive and extensive variables is extensive E. The ratio of any extensive variable to mass will be an extensive variable Choose the correct combination of statements from the options given below:

The correct answer is Option 3. Full mathematical solution steps and hints are accessible in the interactive StemCET workspace.

Physics Q33 – JEE-MAIN 2026

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Home Physics ThermodynamicsQuestion #511

Consider the following statements: A. Zeroth law of thermodynamics gives concept of temperature B. First law of thermodynamics gives concept of internal energy C. In isothermal expansion of ideal gas,

Δ Q \neq Δ W

D. Product of intensive and extensive variables is extensive E. The ratio of any extensive variable to mass will be an extensive variable Choose the correct combination of statements from the options given below:

Clue 1 of 3: Laws of Thermodynamics

Recall the fundamental concepts introduced by the Zeroth and First Laws of Thermodynamics.

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Step 1: Evaluate Statements A, B, and C✦ Active

Statement A: The Zeroth Law of Thermodynamics states that if two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. This law establishes the concept of temperature as a measurable property. So, statement A is TRUE.

Statement B: The First Law of Thermodynamics, $Δ U = Δ Q - Δ W$ , defines the change in internal energy ( $Δ U$ ) of a system in terms of heat added ( $Δ Q$ ) and work done by the system ( $Δ W$ ). Thus, it gives the concept of internal energy. So, statement B is TRUE.

Statement C: For an ideal gas undergoing an isothermal process, the temperature remains constant. Since the internal energy of an ideal gas depends only on temperature, $Δ U = 0$ . According to the First Law of Thermodynamics, $Δ U = Δ Q - Δ W$ . If $Δ U = 0$ , then $Δ Q = Δ W$ . Therefore, the statement $Δ Q \neq Δ W$ is FALSE.

Step 2: Evaluate Statements D and E○ Expand

Statement D: An intensive variable is independent of the amount of matter (e.g., pressure, temperature, density), while an extensive variable depends on the amount of matter (e.g., mass, volume, internal energy). The product of an intensive and an extensive variable is an extensive variable. For example, Pressure (intensive) $\times$ Volume (extensive) = Work (extensive). Or, Molar heat capacity (intensive) $\times$ Moles (extensive) = Heat capacity (extensive). So, statement D is TRUE.

Statement E: The ratio of two extensive variables is an intensive variable. For example, Volume (extensive) / Mass (extensive) = Density (intensive). Internal energy (extensive) / Mass (extensive) = Specific internal energy (intensive). Therefore, the statement that the ratio of any extensive variable to mass will be an extensive variable is FALSE.

Step 3: Identify the Correct Combination○ Expand

Based on the evaluation, statements A, B, and D are TRUE. Statements C and E are FALSE. The correct combination is A, B and D Only.

💡 Teacher's Secret Hint

Always double-check the definitions of intensive and extensive properties and their mathematical operations.

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Physics Question 33 – JEE-MAIN 2026

Clue 1 of 3: Laws of Thermodynamics

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