A positive point charge q is placed at a distance 2 R from the su… - Vidyadip

MCQ

A positive point charge $q$ is placed at a distance $2 R$ from the surface of a metallic shell of radius $R$. The electric field at centre of shell due to induced charge has magnitude

A
Zero
✓
$\frac{1}{4 \pi \varepsilon_0} \frac{q}{9 R^2}$
C
$\frac{1}{4 \pi \varepsilon_0} \frac{q}{4 R^2}$
D
$\frac{1}{4 \pi \varepsilon_0} \frac{q}{R^2}$

✓

Answer

Correct option: B.

$\frac{1}{4 \pi \varepsilon_0} \frac{q}{9 R^2}$

b
(b)

$\vec{E}_{ int }+\vec{E}_{ ext }=0$

$\vec{E}_{ int }=\vec{E}_{ ext }$

$\vec{E}_{ int }=\frac{k q}{9 R^2}$

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