JEE Main 2015PhysicsUnits and DimensionsMediumMCQ

JEE Main 2015 — Units and Dimensions Question with Solution

JEE Main 2015 (11 Apr Online)

Question

If electronic charge e, electron mass m, speed of light in vacuum c and Planck's constant h are taken as fundamental quantities, the permeability of vacuum μ0 can be expressed in units of:

Choose an option

Show full solutionCorrect option: D
Correct answer
Dhce2

Step-by-step explanation

Magnetic potential energy inside a solenoid is

U=12LI2 Where L=self-inductor⇒U=12μ0n2A lI2

∵n= number of turns per unit length

=Nl

U=12μ0Nl2Al I2

U=12μ0N2l2Al I2 

μ0=2UlN2AI2

Dimensionally, U=hcλ

I=eT

A=l2

l=l′

μ0=hcλ [l]l2t2e2

=hλte2=hce2

μ0=hce2

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About this question

This is a previous-year question from JEE Main 2015, covering the Units and Dimensions 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.