A non-conducting sphere of radius `R = 50 mm` charged uniformly with surface density `sigma = 10.0 muC//m^(2)` rotates with an angular velocity `omega = 70` rad/s about the asxis passign thorugh its centre. Find the magnetic induction at the centre of the sphere.

A non-conducting thin disc of radius R charged uniformly over one side with surface density sigma , rotates about its axis with an angular velocity omega . Find (a) the magnetic field induction at the centre of the disc (b) the magnetic moment of the disc.

A non-conducting thin disc of radius R and mass m having charge uniformly over one side with surface density sigma rotates about its axis with an angular velocity omega . Find : (a) the magnetic induction at the centre of the disc, (b) the magnetic moment of the disc. ( c) the ratio of magnetic moment and angular momentum of disc.

A non-conducting thin disc of radius R charged uniformly over one side with surface density s rotates about its axis with an angular velocity omega . Find (a) the magnetic induction at the centre of the disc, (b) the magnetic moment of the disc.

A hollow non conducting sphere of radius R has a positive charge q uniformly distributed on its surface. The sphere starts rotating with a constant angular velocity 'omega' about an axis passing through center of sphere, as shown in the figure. Then the net magnetic field at center of the sphere is

A sphere of radius R, uniformly charged with the surface charge density sigma rotates around the axis passing through its centre at an angular velocity. (a) Find the magnetic induction at the centre of the rotating sphere. (b) Also, find its magnetic moment.

A conducting ring of radius r having charge q is rotating with angular velocity omega about its axes. Find the magnetic field at the centre of the ring.

A copper ball of mass m = 1 kg with a radius of r = 10 cm rotates with angular velocity omega = 2 rad//s about an axis passing through its centre. The work should be performed to increase the angular velocity of rotation of the ball two fold is.

A shpere of radius r carries a surface charge a density sigma = ar , where a is a constant, vector and r is radius vector of a point of the sphere ralative to its centre. Find the electric field strength vector at the centre relative at the centrre of the sphere.

A non conducting sphere of radius R is charged uniformly. At what distance from its surface is the electrostatic potential is half the potential at its centre ?