Question

If a charged spherical conductor of radius 10cm has potential v at a point distant 5cm from its centre, then the potential at a point distant 15cm from the centre will be ….. 

(A) (1/3)V 

(B) (3/2)V 

(C) 3V 

(D) (2/3)V

Answer 1

The correct option (D) (2/3)V

Explanation:

radius of sphere = 10cm

at 5 cm from centre, potential is V

point at distance 15 cm from sphere will be on surface of sphere

Potential inside sphere is same as on it's surface

hence V = [(k ∙ Q)/(10)]

now V at 15 cm = V' = (kQ/15)

∴ (V/V') = [(kQ/10)/(kQ/15)] = (15/10) = (3/2)

∴ V' = (2/3)V