A conducting sphere of radius 10 cm has an unknown charge. If the electric field 20 cm from the centre of the sphere is `1.5xx10^(3) N//C` and points radially inward, what is the net charge on the sphere?

Explanation

(a) `-10^(3) N m^(2)//C` because the charge enclosed is the same in the two cases
(b) -8.8 nc