JEE Main 2018PhysicsMagnetic Effects of CurrentMediumMCQ

JEE Main 2018 — Magnetic Effects of Current Question with Solution

JEE Main 2018 (08 Apr)

Question

The dipole moment of a circular loop carrying a current I, is m and the magnetic field at the centre of the loop is B1 . When the dipole moment is doubled by keeping the current constant, the magnetic field at the centre of the loop is B2  . The ratio B1B2 is:

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Show full solutionCorrect option: D
Correct answer
D2

Step-by-step explanation

m=magnetic dipole moment=IA. For Loop1, m=Iπr2, B1=μ0i2r
For Loop2. If current is constant m is doubled.  r 1 = 2 r .  B 2 = μ0 i 2 2 r .B1B2=2

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About this question

This is a previous-year question from JEE Main 2018, covering the Magnetic Effects of Current 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.