.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

A long thin flat sheet has a uniform surface charge density sigma . The magnitude of the electric field at a distance .r. from it is given by

A charged disc of radius 3 m has charge density sigma . Electric field at a distance of 4 m from its centre on axis is _______

A charged disc of radius 3 m has charge density sigma . Electric field at a distance of 4 m from its centre on axis is _______

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

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 :