Easy MCQ +4 / -1 PYQ · JEE Mains 2023

Match List I with List II

List I List II
A. Isothermal Process I. Work done by the gas decreases internal energy
B. Adiabatic Process II. No change in internal energy
C. Isochoric Process III. The heat absorbed goes partly to increase internal energy and partly to do work
D. Isobaric Process IV. No work is done on or by the gas

Choose the correct answer from the options given below :

  1. A A-I, B-II, C-IV, D-III
  2. B A-II, B-I, C-III, D-IV
  3. C A-II, B-I, C-IV, D-III Correct answer
  4. D A-I, B-II, C-III, D-IV

Solution

$\Delta \mathrm{U}=\mathrm{nC}_{\mathrm{v}} \Delta \mathrm{T}$<br/><br/> For isothermal process $\mathrm{T}$ is constant<br/><br/> So $\Delta \mathrm{U}=0$<br/><br/> $\mathrm{A} \longrightarrow \mathrm{II}$<br/><br/> Adiabatic process<br/><br/> $$ \begin{aligned} & \Delta \mathrm{Q}=0 \\\\ & \Delta \mathrm{Q}=\Delta \mathrm{U}+\Delta \mathrm{W} \\\\ & \Delta \mathrm{U}=-\Delta \mathrm{W} \end{aligned} $$<br/><br/> Work done by gas is positive<br/><br/> So $\Delta \mathrm{U}$ is negative<br/><br/> $\text { B } \longrightarrow \text { I }$<br/><br/> For Isochoric process $\Delta \mathrm{W}=0$<br/><br/> $\mathrm{C} \longrightarrow \mathrm{IV}$<br/><br/> For Isobaric process<br/><br/> $$ \begin{aligned} & \Delta \mathrm{W}=\mathrm{P} \Delta \mathrm{V} \neq 0 \\\\ & \Delta \mathrm{U}=\mathrm{nC}_{\mathrm{V}} \Delta \mathrm{T} \neq 0 \end{aligned} $$<br/><br/> Heat absorbed goes partly to increase internal energy and partly to do work.

About this question

Subject: Physics · Chapter: Thermodynamics · Topic: Zeroth and First Law

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