In a neutral conducting hollow sphere of inner and outer radii 5 cm and 10 cm respectively, a point charge Q = 1C is placed at point A, that is 3 cm from the centre C of the hollow sphere. An external uniform electric field of magnitude 20 N/C is also applied. Net electric force on this charge is 15 N, away from the centre of the sphere as shown. Then find :
(a) Force due to external electric field on the outer surface of the shell
(b)Net force on shell.
(c) Net force on point charge due to shell.

Answer

(a) 20 N right hand side (b) 35 N right hand side (c) 35 N left hand side