A large solid sphere with uniformly distributed positive charge has a smooth narrow tunnel through its centre. A small particle with negative charge, initially at rest far from the sphere, approaches it along the line of tunnel, reaches its surface with a speed v, and passes through the tunnel. Its speed at the centre of the sphere will be

A point Q lies on the perpendicular bisector of an electric dipole of dipole moment p. If the distance of Q from the dipole is r, (much larger than the size of the dipole) then electric field at Q is proportional to

Two concentric spheres of radii R and r have similar charges with equal surface densities (σ). What is the electric potential at their common centre?

A cylinder of radius R and length L is placed in a uniform electric field E parallel to the axis of the cylinder. The total flux from the surface of cylinder is given by

There is an electric field E in x - direction. If the work done on moving a charge of 0.2 C through a distance of 2 m along a line making an angle 60^o with x-axis is 4 J, then what is the value of E?

The four capacitors, each of 25 μF are connected as shown in figure. The DC voltmeter reads 200 V. The charge on one each plate of capacitor is 

A particle of mass m and charge q is placed at rest in a uniform electric field E and then released. The Kinetic energy attained by the particle after moving a distance y is

The work done in carrying a charge Q once round the circle of radius r with charge Q at the centre of the circle is

Intensity of an electric field (E) depends on distance r due to a dipole, is related as

The study of the effects associated with electric charges at rest is called