JEE Main 2018PhysicsCurrent ElectricityElectric Power And Heating Effect Of CurrenteasyMCQ

JEE Main 2018 — Current Electricity Question with Solution

From: JEE Main 2018 (Online) 15th April Evening Slot

Question

A constant voltages is applied between two ends of a metallic wire. If the length is halved and the radius of the wire is doubled, the rate of heat developed in the wire will be :

Choose an option

Show full solutionCorrect option: D
Correct answer
DIncreased 8 times

Step-by-step explanation

Since rate of heat rate of heat , where ; here r is radius of wire and L is length of wire. Therefore,

.

Thus, rate of heat .

When length in halved and radius is doubled then, rate of heat

Therefore, rate of heat developed in wire will be increased 8 times.

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About this question

This is a previous-year question from JEE Main 2018, 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.