.A thin disc of radius b=2a has a concentric hole of radius a' in it.It carries uniform charge density sigma on it.If the electric field on its axis at distance 'd' from the centre is given as 'nd' then value of 'n' is

A thin disc of radius "b=2a" has a concentric hole of radius ' "a" ' in it (see figure).It carries uniform surface charge sigma on it.If the electric field on its axis at height 'h'(h << a) from its centre is given as 'Ch' then value of 'C' is

A sphere of radius R has a charge density sigma . The electric intensity at a point at a distance r from its centre is

An insulated sphere of radius r haas a uniform volume charge density lambda . The electric field at a point A , which is at distance r from its centre is given by (R gt r)

Consider a thin spherical shell of radius R consisting of uniform surface charge density sigma . The electric field at a point of distance x from its centre and outside the shell is

For a uniformly charged ring of radius R, the electric field on its exis has the largest magnitude at a distance h from its centre. Then value of h 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.

A sphere of radius 2R has a uniform charge density p. The difference in the electric potential at r = R and r = 0 from the centre is:

There is a hemisphere of radius R having a uniform volume charge density rho . Find the electric potential and field at the centre