JEE Main 2023PhysicsMagnetic Properties of MatterMediumNumerical

JEE Main 2023 — Magnetic Properties of Matter Question with Solution

JEE Main 2023 (12 Apr Shift 1)

Question

A compass needle oscillates 20 times per minute at a place where the dip is 30o and 30 times per minute where the dip is 60o. The ratio of total magnetic field due to the earth at two places respectively is 4x. The value of x is

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Show full solutionCorrect answer: 243
Correct answer
243

Step-by-step explanation

The formula for time period is given by 

T=2πIMBH

⇒T=2πIMBcosθ

Let

 θ1=30°θ2=60°

The ratio of the time periods is,

T1T2=60206030=B2cos60°B1cos30°=B2B1×1232

⇒B1B2=4243

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About this question

This is a previous-year question from JEE Main 2023, covering the Magnetic Properties of Matter 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.