JEE Main 2016PhysicsElectrostaticsHardMCQ

JEE Main 2016 — Electrostatics Question with Solution

JEE Main 2016 (03 Apr)

Question

The region between two concentric spheres of radii 'a' and 'b', respectively (see figure), has volume charge density ρ=Ar , where A is a constant and r is the distance from the centre. At the centre of the spheres is a point charge Q. The value of A such that the electric field in the region between the spheres will be constant, is:

Choose an option

Show full solutionCorrect option: C
Correct answer
CQ2πa2

Step-by-step explanation

E=E1+E2

⇒E=KQ+∫ar4πx2dxAxr2

E=KQr2+4πAr22r2-a22r2

dEdr=0

⇒-2Qr3+8πAa22r3=0

A=Q2πa2

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About this question

This is a previous-year question from JEE Main 2016, covering the Electrostatics 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.