Question

The electrostatic potential on the surface of uniformly charged spherical shell of radius R = 10 cm is 120 V. The potential at the centre of shell, at a distance r = 5 cm from centre, and at a distance r = 15 cm from the centre of the shell respectively, are:

• A. 120V, 120V, 80V
• B. 40V, 40V, 80V
• C. 0V, 0V, 80V
• D. 0V, 120V, 40V

Hint:

Remember that the electrostatic potential inside a uniformly charged spherical shell is constant and equal to the potential on the surface. Outside the shell, the potential varies inversely with the distance from the center.

Answer 1

The Correct Option is A

Potential inside shell is equal to potential on surface. 

\( V_{in} = V_{surface} = \frac{kQ}{R} = 120 V \) at r = 15 cm 

\( V = \frac{kQ}{r} = \frac{120 \times 10}{15} = 80 V \)