JEE Main 2022 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 25 July 2022, Shift 2, Physics Q45

Question 45 of 90 in this shift, Physics question 15 of 30, Section A.

Let

\eta_1

is the efficiency of an engine at

\mathrm{T_1}

= 447°C and

\mathrm{T_2}

= 147°C while

\eta_2

is the efficiency at

\mathrm{T_1}

= 947°C and

\mathrm{T_2}

= 47°C The ratio

\frac{\eta_1}{\eta_2}

will be :

(1)0.41
(2)0.56Official answer
(3)0.73
(4)0.70

Official answer

Option 2

NTA final key.

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

Same idea in other shifts

Asked 15× 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
12 Apr 2023, Shift 1 · Q38An engine operating between the boiling and freezing points of water will have A. efficiency more than 27%. B. efficiency less than the…MediumOther
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
30 Jul 2022, Shift 2 · Q7A Carnot engine is operating between the two reservoirs of temperature 227 $^\circ$ C and 127 $^\circ$ C respectively. If the engine…EasySingle correct
24 Jun 2022, Shift 1 · Q47A 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…MediumSingle correct
24 Jun 2022, Shift 2 · Q35A Carnot engine takes 5000 kcal of heat from a reservoir at $727^{\circ}C$ and gives heat to a sink at $127^{\circ}C$ . The work done by…EasySingle correct
26 Jun 2022, Shift 1 · Q37The efficiency of a Carnot's engine, working between steam point and ice point, will be :EasySingle correct
3 Aug 2021, Shift 1 · Q5A carnot engine working at source temperature 400 $K$ , takes 500 $J$ heat from the source and rejects 300 $J$ to sink. What is the…EasySingle correct

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 108 of the 174 JEE Main shifts held from 2017 to 2026.