A thin semi-circular ring of radius r has a positive charge q distributed uniformly over it. The net field `vecE` at the centre O 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 ring of radius a contains a charge q distributed. uniformly ober its length. Find the electric field at a point. on the axis of the ring at a distance x from the centre.

A ring of radius a contains a charge q distributed. uniformly ober its length. Find the electric field at a point. on the axis of the ring at a distance x from the centre.

A ring of radius a contains a charge q distributed. uniformly ober its length. Find the electric field at a point. on the axis of the ring at a distance x from the centre.

Figure shows a rod AB, which is bent in a 120^(@) circular arc of radius R. A charge (-Q) is uniformly distributed over rod AB. What is the electric field vecE at the centre of curvature O ?