Question

The electric field intensity at point O is

• A. Zero
• B. $\frac{q}{4\pi {ϵ}_0}[\frac{1}{r^2}-\frac{1}{R_1^2}+\frac{1}{R_2^2}]$
• C. $\frac{q}{4\pi {ϵ}_0}[\frac{1}{r^2}-\frac{1}{R_1^2}]$
• D. None of these

Answer 1

The correct option is D None of these

The distance of point charge $q$ from O is $r$.

Now due to induction, inner surface of sphere get negative charge $-q$.

And since whole sphere is neutral, outer surface of sphere gets charge $+q$.

And field inside a charged sphere due to charge on sphere is $0$.

Hence field at $O$ is only due to point charge $q$-

$E=\frac{q}{4\pi {ϵ}_o{r}^2}$

Answer-(D)