Question

A sphere has a surface uniformly charged with 0.75 C. At what distance from its center is the potential 8 MV (megavolts)?

Answer 1

Given:

A sphere has a surface uniformly charged with 0.75 C.

To find:

Distance from its center where the potential is 8 MV?

Calculation:

General expression of electrostatic potential for a solid sphere is :

• Let's assume that r > Radius of the sphere.

$\rm\therefore \: V = \dfrac{q}{4\pi \epsilon_{0}r}$

$\rm\implies\: 8 \times {10}^{6} = \dfrac{(9 \times {10}^{9}) \times 0.75}{r}$

$\rm\implies\: r = \dfrac{(9 \times {10}^{9}) \times 0.75}{8 \times {10}^{6} }$

$\rm\implies\: r = 0.84 \times {10}^{3} \: m$

$\rm\implies\: r = 840 \: m$

So, distance from centre of sphere is 840 m.