JEE Main 2022PhysicsThermal Properties of MatterMediumMCQ

JEE Main 2022 — Thermal Properties of Matter Question with Solution

JEE Main 2022 (29 Jul Shift 1)

Question

Two metallic wires of identical dimensions are connected is series. If σ1 and σ2 are the conductivities of the these wires respectively, the effective conductivity of the combination is :

Choose an option

Show full solutionCorrect option: B
Correct answer
B2σ1σ2σ1+σ2

Step-by-step explanation

Let length of wire be l,
Area of wire as A
For equivalent wire length =2l & area will be A

As the wires are connected in series combination, the thermal resistance

Req=R1+R2

⇒2lσeq A=lσ1 A+lσ1 A

⇒2σeq =1σ1+1σ2⇒σeq =2σ1σ2σ1+σ2

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About this question

This is a previous-year question from JEE Main 2022, 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.