Question

In the figure two conducting concentric spherical shells are shown. If the electric potential at the centre is 20V and the electric potential of the outer shell is 5V, then the potential of the inner shell is
(a) 5V
(b) 15V
(c) 20V
(d) 25V

Answer 1

(b) 15 V

figure required ...

(BTW guessing two concentric spheres)

Vc - potential at center = 20 V

Vi - potential due to inner shell

Vo - potential due to outer shell = 5 V

Since, at center, net potential will due both shells.

Vc = Vi + Vo

=> 20 = Vi + 5

=> Vi = 20 - 5 = 15 V ..... answer...

Answer 2

In figure two conducting concentric spherical shells are shown. If the electric potential at the center is 20V and the electric potential of the outer shell is 5V, then the potential of the inner shell is 20V. Option(c) is the correct answer.

• In the inner shell, the electric field is zero which means there is no electric field inside it. So, the potential inside the inner shell is equal to the potential at the center which is 20V.

• The addition of charges on the outer shell does not have any effect on the potential difference between the 2 spherical shells.