Question

A hollow spherical conducting shell of inner radius $r_1$ and other radius $r_2$ has a charge Q. A charge -q is placed at the centre of the sphere. The surface charge densities on the inner and outer surfaces of the sphere will be respectively:-

• A. $\frac{q}{4\pi r_1^2}$ and $\frac{q}{4\pi r_2^2}$
• B. $\frac{-q}{4\pi r_1^2}$ and $\frac{Q+q}{4\pi r_2^2}$
• C. $\frac{q}{4\pi r_1^2}$ and $\frac{Q-q}{4\pi r_2^2}$
• D. 0 and $\frac{Q-q}{4\pi r_2^2}$

Answer 1

The correct option is B $\frac{-q}{4\pi r_1^2}$ and $\frac{Q+q}{4\pi r_2^2}$

$\begin{array}{c}{\sigma }_1=\frac{-q}{4\pi r_1^2}\\ {\sigma }_2=\frac{Q+q}{4\pi r_2^2}\\ Hence,\\ optionBiscorrectanswer.\end{array}$