A ring of radius R is marked in six equal parts and these parts are charged uniformly with a charge of magnitude Q but positive and negative alternately as shown. Then the electric field at centre of ring will be

A ring of radius R is marked in six equal parts and these parts are charged uniformly each with a charge of magnitude Q but positive and negative alternately as shown. The electric field at centre of ring will be

Charges q is uniformly distributed over a thin half ring of radius R . The electric field at the centre of the ring is

A charge Q is uniformly distributed only on the fourths portion of a ring of radius R . The elctric potential at centre of ring is

A ring of radius R is charged uniformly with a charge +Q . The potential at a point on its axis at a distance 'r' from any point on ring will be-

A charge Q is distributed uniformly on a ring of radius R as shown in the following diagrams. Find the electric potential at the centre O of the ring

A circular ring of radius r carries a charge Q uniformly spread on it. A small length dl is cut off. Find the electric field at the centre due to the remaining wire.

A non conduction ring of raducs R Has uniformly distributed positive charge Q.A small part of the ring of length d, is removed (d lt lt R) . The electric field at the centre of the ring now be .

A charge Q is distributed uniformly on a ring of radius R as shown in the following diagrams. Find the electric potential at the center O of the ring. (a)

A ring of radius R has charge -Q distributed uniformly over it. Calculate the charge that should be placed at the center of the ring such that the electric field becomes zero at apoint on the axis of the ring at distant R from the center of the ring.

Two semicircular rings lying in same plane, of uniform linear charge density lambda have radius r and 2r. They are joined using two straight uniformly charged wires of linear charge density lambda and length r as shown in figure. The magnitude of electric field at common centre of semi circular rings is -