JEE Main 2021PhysicsThermal Properties of MatterMediumNumerical

JEE Main 2021 — Thermal Properties of Matter Question with Solution

JEE Main 2021 (27 Aug Shift 1)

Question

A rod CD of thermal resistance 10.0KW-1 is joined at the middle of an identical rod AB as shown in figure. The ends A, B and D are maintained at 200°C,100°C and 125°C respectively. The heat current in CD is P W. The value of P is

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Show full solutionCorrect answer: 2
Correct answer
2

Step-by-step explanation

 

QAC+QDC=QCB

KA(200-t)ℓ2+KA(125-t)ℓ=(t-100)KAℓ2

400-2t+125-t=2t-200

725=5t

t=145ºC

QCD=KA(145-125)ℓ=20ℓKA=2 W

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About this question

This is a previous-year question from JEE Main 2021, covering the Thermal Properties of Matter chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.