Verified Solution • 2025–26 Session moderate

QJEEM21Ph92c1: JEE Main 2021 Physics - Class 12 JEEM21Ph92c1 Solution: A solid metal sphere of radius R having charge q is enclosed…

A solid metal sphere of radius R having charge q is enclosed inside the concentric spherical shell of inner radius a and outer radius b as shown in the figure. The approximate variation electric field E→\overrightarrow E as a function of distance r from centre O is given by

JEE Main 2021 (Online) 26th August Morning Shift Physics - Electrostatics Question 119 English

Multiple Choice Options

  • A https://ik.imagekit.io/novatra/photos/d5f4689c1e9dd3f1feed89548a384d7ff84f131aba8ebc4b5b512c564d22ceac.webp
  • B https://ik.imagekit.io/novatra/photos/2eb8f247ea3adc3986ca2acdcd36ae792e0dedfa8b5b6c52ef0bc5afbfc06b53.webp
  • C https://ik.imagekit.io/novatra/photos/4bfdf9d68d33c101fe8e77ea553ba2f5def3aadcc7d078ad828ac62b48eb89cf.webp
  • D https://ik.imagekit.io/novatra/photos/420eb78383d3f43e0c6fd40a1e27a434d4c2c16bd5adf9c0beecdc8c36504259.webp

Step-by-Step Verified Solution

Considering outer spherical shell is non-conducting.

Electric field inside a metal sphere is zero.

r < R ⇒\Rightarrow E = 0

r > R ⇒\Rightarrow E = kQr2{{kQ} \over {{r^2}}}

JEE Main 2021 (Online) 26th August Morning Shift Physics - Electrostatics Question 119 English Explanation 1
Option (b)

Considering outer spherical shell is conducting

JEE Main 2021 (Online) 26th August Morning Shift Physics - Electrostatics Question 119 English Explanation 2
r < R, E = 0

R ≤\le r < a

E = kQr2{{kQ} \over {{r^2}}}

a ≤\le r < b,

E = 0

r ≥\ge b,

E = kQr2{{kQ} \over {{r^2}}}

JEE Main 2021 (Online) 26th August Morning Shift Physics - Electrostatics Question 119 English Explanation 3

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