A thin ring of radius equal to 25 cm carries a uniformly distributed charge of 4.7 nC. What is the electric field and potential difference at the center of the ring?

Answer 1

Because of symmetry, the field at the center is zero.

Since the potential due to charge element dq (relative to the value at infinity)is k dq/r, and all charges are equidistant from the center, the potential is k Q/R

k is the Coulomb constant. Q is the total charge. R is the ring radius