Electric Charges And Fields

After coalescing, volume remains conserved.
Volume of identical drops = volume of one big drop
i.e,
or ...(i)
where is radius of bigger drop and is radius of each smaller drop.
Potential of each smaller drop,
...(ii)
Potential of bigger drop

[from E (i)]
[from E (ii)]

The electric field inside a spherical charge is everywhere zero, that is

But point is outside the inner sphere, hence for a point very close to the surface the intensity of electric field is given by

Given,
Therefore,

According to this law, the net electric flux through any dosed surface is equal to the net charge inside the surface divided by ''.
Therefore,
Let be the charge, due to which flux is entering the surface

or
Let be the charge, due to which flux is leaving, the surface

or
So, electric charge inside the surface

A pendulum bob of weight and carrying a charge is suspended in the electric field . Suppose that it comes to rest at point , so that it makes an angle with the vertical as shown. At point , the bob is acted upon by the following three forces.

(i) Weight mg acting vertically downward.
(ii) Tension in the string along
(iii) Electrostatic force on the bob along horizontal.
Since the bob is in equilibrium under the action of the forces and , these forces can be represented by the sides and of triangle ANS.
Therefore,

and