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Saturday, 31 October

JEE Main 2020 · PhysicsMultiple choiceSingle correctEasyCalculation

JEE Main 8 January 2020, Shift 2, Physics Q7

Question 7 of 75 in this shift, Physics question 7 of 25, Section A.

A Carnot engine having an efficiency of 110\frac{1}{10} is being used as a refrigerator. If the work done on the refrigerator is 10 J10\ \mathrm{J}, the amount of heat absorbed from the reservoir at lower temperature is :
  1. (1)100 J100\ \mathrm{J}
  2. (2)99 J99\ \mathrm{J}
  3. (3)90 J90\ \mathrm{J}Official answer
  4. (4)1 J1\ \mathrm{J}

Official answer

Option 3

NTA final key (Jan 2020).

Chapter
Thermodynamics
Topic
Heat Engines and Refrigerators
Idea tested
Efficiency and COP Conversion

Same topic in other shifts

All Heat Engines and Refrigerators questions
  1. 8 Apr 2023, Shift 2 · Q34Work done by a Carnot engine operating between temperatures 127∘127^\circC and 27∘27^\circC is 2 kJ. The amount of heat transferred to the…EasySingle correct
  2. 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
  3. 25 Jul 2022, Shift 2 · Q45Let η1\eta_1 is the efficiency of an engine at T1\mathrm{T_1} = 447°C and T2\mathrm{T_2} = 147°C while η2\eta_2 is the efficiency at…EasySingle correct
  4. 27 Jul 2022, Shift 2 · Q38In 1st^{st} case, Carnot engine operates between temperatures 300 K and 100 K. In 2nd^{nd} case, as shown in the figure, a combination of…EasyDiagram basedHas a figure
  5. 28 Jul 2022, Shift 1 · Q37A Carnot engine has efficiency of 50%. If the temperature of sink is reduced by 40∘40^\circC, its efficiency increases by 30%. The…MediumSingle correct
  6. 30 Jul 2022, Shift 2 · Q7A Carnot engine is operating between the two reservoirs of temperature 227 ∘^\circC and 127 ∘^\circC respectively. If the engine…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.