Electrostatics ...

A simple pendulum consists of a small sphere of mass m suspended by a thread of length l. The sphere carries a positive charge q. The pendulum is placed in a uniform electric field of strength E directed Vertically upwards. If the electrostatic force acting on the sphere is less than gravitational force the period of pendulum is

In Millikan’s oil drop experiment an oil drop carrying a charge Q is held stationary by a p.d. 2400 v between the plates. To keep a drop of half the radius stationary the potential difference had to be made 600 v. What is the charge on the second drop ?

Equal charges q are placed at the vertices A and B of an equilateral triangle ABC of side a. The magnitude of electric field at the point c is .........

If electron in ground state of H-atom is assumed in rest then dipole moment of electron proton system of H-atom is ............... . Orbit radius of H atom in ground state is 0.56 Å

At what angle θ a point P must be located from dipole axis so that the electric field intensity at the point is perpendicular to the dipole axis ?