Question

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 figure. The approximate variation electric field $\vec{E}$ as a function of distance $r$ from centre $O$ is given by

• A.
• B.
• C.
• D.

Answer 1

Answer: (A)

Considering outer spherical shell is nonconducting
Electric field inside a metal sphere is zero.
$r<R\Rightarrow E=0$
$r>R\Rightarrow E=\frac{kQ}{r^2}$

Option (2)
Considering outer spherical shell is conducting

$r<R,E=0$
$R\le r<a$
$a\le r<b$
$r\ge b$
$E=\frac{kQ}{r^2}$
$E=0$
$E=\frac{kQ}{r^2}$

Option (1)