JEE Main 2022 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 24 June 2022, Shift 1, Physics Q47

Question 47 of 90 in this shift, Physics question 17 of 30, Section A.

A Carnot engine whose heat sinks at

27^\circ

C, has an efficiency of 25%. By how many degrees should the temperature of the source be changed to increase the efficiency by 100% of the original efficiency ?

(1)Increases by $18^\circ$ C
(2)Increases by $200^\circ$ COfficial answer
(3)Increases by $120^\circ$ C
(4)Increases by $73^\circ$ C

Official answer

Option 2

NTA final key (2022 Session 1).

Chapter: Thermodynamics
Topic: Heat Engines and Refrigerators
Idea tested: Carnot Efficiency Limit

Same idea in other shifts

Asked 4× in all

8 Apr 2023, Shift 2 · Q34Work done by a Carnot engine operating between temperatures $127^\circ$ C and $27^\circ$ C is 2 kJ. The amount of heat transferred to the…EasySingle correct
28 Jul 2022, Shift 1 · Q37A Carnot engine has efficiency of 50%. If the temperature of sink is reduced by $40^\circ$ C, its efficiency increases by 30%. The…MediumSingle correct
16 Mar 2021, Shift 2 · Q26For an ideal heat engine, the temperature of the source is $127^\circ$ C. In order to have 60% efficiency the temperature of the sink…EasyNumerical 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. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.