posted by sandhu .
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?
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