A half ring of radius R has a charge of `lambda` per unit length. The electric force on 1C charged placed at the center is

A small element l cut from a circular ring of radius a and lamda charge per unit length. The net electric field at the centre of ring is

A semi-cricular arc of radius a is charged unformly and the charge per unit length is lambda . The electric field at the centre is

A semicircular are of radius a is charged uniformly and the charge per unit length is lambda . The electric field at its centre is

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.

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.

A half ring of radius r has a linear charge density lambda .The potential at the centre of the half ring is

A half ring of radius r has a linear charge density lambda .The potential at the centre of the half ring is

A quarter ring of radius R is having uniform charge density lambda . Find the electric field and potential at the centre of the ring.