A rubber balloon is given a charge Q distributed uniformly over its surface. Then

A spherical rubber ballon carries some charge distributed uniformly over its surface. The balloon is blown up to increase in its size. How does the total electric flux coming out of the surface change?

A hollow sphere of radius a carries a total charge Q distributed uniformly over its surface. A small area dA of the sphere is cut off. Find the electric field at the centre due to the remaining sphere.

A spherical shell made of plastic, contains a charge Q distributed uniformly over its surface. What is the electric field inside the shell? If the shell is hammered to deshape it without altering the charge. Will the field inside be changed? What happend if the shell is made of a metal?

A hollow tube is carrying an electric current along its length distributed uniformly over its surface. The magnetic field

A thin disc of radius R has charge Q distributed uniformly on its surface. The disc is rotated about one of its diametric axis with angular velocity omega . The magnetic moment of the arrangement is

A thin disc of dielectric material, with a total charge +q distributed uniformly over its surface rotates n times per second about an axis perpendicualr to the surface of the disc and passing through its center. Find the magnetic induction at the center of the disc. The radius of the disc is equal to r.

A ring of dielectric material, with a total charge +q distributed uniformly over its surface, rotates with angular speed omega. Find the magnetic moment of the ring .Compare its magnetic moment with its angular momentum , assuming that its mass is m.

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.