Question

Two pieces of plas- tic, a full ring and a half ring, have the same radius and charge density. Which electric field at the center has the greater magnitude? Discuss and defend your answer.

Answer 1

Answer: The magnitude of the Electric Field at the centre of both plastic would be equal to Zero {i.e E =0}

Explanation: A plastic either full circle or half is an insulator, and the charges in an insulator cannot move around.

Therefore, thier electric potential p(r) = 0.

Recall that,

Electric field intensity E = first derivative of p(r) with respect to r ( radius).since p(r) = 0, E = 0 inside both plastic.