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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceDiagram basedEasyData or graph

JEE Main 25 February 2021, Shift 2, Physics Q5

Question 5 of 90 in this shift, Physics question 5 of 30, Section A.

Thermodynamic process is shown below on a P-V diagram for one mole of an ideal gas. If V2=2V1V_2 = 2V_1 then the ratio of temperature T2/T1T_2/T_1 is :

The figure, in words

P-V diagram (P vertical axis, V horizontal axis). A decreasing curve labelled PV1/2PV^{1/2} = constant from point 1 (P1, V1, T1) at upper left to point 2 (P2, V2, T2) lower right, with dashed vertical lines down to V1 and V2 on the V axis.
  1. (1)12\frac{1}{\sqrt{2}}
  2. (2)2\sqrt{2}Official answer
  3. (3)12\frac{1}{2}
  4. (4)2

Official answer

Option 2

NTA final key.

Chapter
Thermodynamics
Topic
Thermodynamic Processes
Idea tested
Polytropic Process Analysis

Same idea in other shifts

Asked 5× in all
  1. 1 Feb 2024, Shift 1 · Q38The pressure and volume of an ideal gas are related as PV32=KPV^{\frac{3}{2}} = K (Constant). The work done when the gas is taken from state A…MediumSingle correct
  2. 30 Jan 2024, Shift 1 · Q38Two thermodynamical processes are shown in the figure. The molar heat capacity for process A and B are CAC_A and CBC_B. The molar heat…HardDiagram basedHas a figure
  3. 25 Feb 2021, Shift 1 · Q29In a certain thermodynamical process, the pressure of a gas depends on its volume as kV3kV^{3}. The work done when the temperature changes…MediumNumerical value
  4. 26 Feb 2021, Shift 2 · Q23The volume V of a given mass of monoatomic gas changes with temperature T according to the relation V = KT23T^{\frac{2}{3}}. The workdone…MediumNumerical value

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. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.