JEE Main 2020PhysicsGravitationHardMCQ

JEE Main 2020 — Gravitation Question with Solution

JEE Main 2020 (02 Sep Shift 2)

Question

The height ‘h’ at which the weight of a body will be the same as that at the same depth ‘h’ from the surface of the earth is (Radius of the earth is R and effect of the rotation of the earth is neglected) 

Choose an option

Show full solutionCorrect option: C
Correct answer
C5R-R2

Step-by-step explanation

GM(R+h)2=GMR3(R-h)
R3=(R+h)2(R-h)
=R2+h2+2hR(R-h)
R3=R3+h2R+2hR2-R2h-h3-2h2R
h3+h2(2R-R)-R2h=0
h3+h2R-R2h=0
h2+hR-R2=0
h=-R±R2+4(1)R22
=-R+5R2
=(5-1)2R

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About this question

This is a previous-year question from JEE Main 2020, covering the Gravitation 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.