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JEE Main 202226 JulyEvening Shift
Exam
JEE Main
Year
2022
Date
26 July
Shift
Evening Shift
Subject
Physics
Chapter
Electrostatics

JEE Main 2022 · 26 July · Evening Shift · Physics · Electrostatics

Two uniformly charged spherical conductors A and B of radii 5mm and...

Two uniformly charged spherical conductors AA and BB of radii 5mm5mm and 10mm10mm are separated by a distance of 2cm2cm. If the spheres are connected by a conducting wire, then in equilibrium condition, the ratio of the magnitudes of the electric fields at the surface of the sphere AA and BB will be

Options

  1. A1:21: 2
  2. B2:12: 1
  3. C1:11: 1
  4. D1:41: 4

Correct answer

B. 2:12: 1

Step-by-step solution

When two conductors are connected by a conducting wire, their potentials become equal. Therefore, VA=VB{V}_{A} = {V}_{B}

The potential of a spherical conductor is given by, V=kQRV = \dfrac{kQ}{R}

⇒kQARA=kQBRB⇒ \dfrac{k{Q}_{A}}{{R}_{A}} = \dfrac{k{Q}_{B}}{{R}_{B}}

⇒Q∝R⇒ Q ∝ R

Now the electric field near the surface of the conductor will be, E=kQR2E = \dfrac{kQ}{{R}^{2}}

⇒EAEB=kQARA2kQBRB2=RBRA⇒ \dfrac{{E}_{A}}{{E}_{B}} = \dfrac{k{Q}_{A}{R}_{A}^{2}}{k{Q}_{B}{R}_{B}^{2}} = \dfrac{{R}_{B}}{{R}_{A}}

⇒EAEB=105=21⇒ \dfrac{{E}_{A}}{{E}_{B}} = \dfrac{10}{5} = \dfrac{2}{1}

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