JEE Main 2022PhysicsCurrent ElectricityMediumNumerical

JEE Main 2022 — Current Electricity Question with Solution

JEE Main 2022 (25 Jun Shift 2)

Question

The length of a given cylindrical wire is increased to double of its original length. The percentage increase in the resistance of the wire will be _____ %

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Show full solutionCorrect answer: 300
Correct answer
300

Step-by-step explanation

As volume is constant, so, length doubled and area reduces to half.

Resistance of a wire is given by R=ρlA, where, ρ is resistivity of a material.

Here, R1=ρlA and R2=ρ2lA2=4R

So percentage increase in the resistance will be =4R-RR×100%=300%

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About this question

This is a previous-year question from JEE Main 2022, covering the Current Electricity 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.