JEE Main 2015PhysicsMagnetic Effects of CurrentHardMCQ

JEE Main 2015 — Magnetic Effects of Current Question with Solution

JEE Main 2015 (11 Apr Online)

Question

A wire carrying current I is tied between points P and Q and is in the shape of a circular arc of radius R due to a uniform magnetic field B (perpendicular to the plane of the paper, as shown in the figure) in the vicinity of the wire. If the wire subtends an angle 2θo at the center of the circle (of which it forms an arch) then the tension in the wire is:

Choose an option

Show full solutionCorrect option: A
Correct answer
AIBR

Step-by-step explanation



Consider any small element dl of arc of angle dθ . Then magnetic force dF=Idl.B outwards  



For equilibrium of element 

Idl B=2T sindθ2

For small angle sinθ≃θ

IdlB=2Tdθ2

Idl B=TdlR

T=IBR

 

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About this question

This is a previous-year question from JEE Main 2015, 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.