Question

The adjacent diagram shows a charge $+Q$ held on an insulating support $S$ and enclosed by a hollow spherical conductor. $O$ represents the centre of the spherical conductor and $P$ is a point such that $OP=x$ and $SP=r$. The electric field at point $P$ will be

• A. $\frac{Q}{4\pi {\epsilon }_0{x}^2}$
• B. $\frac{Q}{4\pi {\epsilon }_0{r}^2}$
• C. zero
• D. None of these

Answer 1

Answer: (A)

Applying Gausss law
$\oint \vec{E}.\vec{d}s=\frac{1}{{\epsilon }_0}{Q}_{\text{enclosed }}$
$E.4\pi x^2=\frac{Q}{{\epsilon }_0}$
$E=\frac{Q}{4\pi {\epsilon }_0{x}^2}$