Electrostatics 3 Question 3
3. The given graph shows variation (with distance $r$ from centre) of
(Main 2019, 11 Jan I)
(a) electric field of a uniformly charged spherical shell
(b) potential of a uniformly charged spherical shell
(c) electric field of a uniformly charged sphere
(d) potential of a uniformly charged sphere
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Answer:
Correct Answer: 3. (d)
Solution:
- For a uniformly charged spherical shell, electric potential inside it is given by
$$ V _{\text {inside }}=V _{\text {surface }}=k q / r _0=\text { constant, } $$
(where $r _0=$ radius of the shell).
and electric potential outside the shell at a distance $r$ is
$$ V _{\text {outside }}=\frac{k q}{r} \Rightarrow \quad V \propto 1 / r $$
$\therefore$ The given graph represents the variation of $r$ and potential of a uniformly charged spherical shell.
