Charge on dipole is
Distance between the charges = 1mm=
Dipole moment is given by-p = q(2a)
=
S1 and S2 are two hollow concentric spheres enclosing charges 2Q and 4Q respectively as shown in the figure.
(i) What is the ratio of electric flux through S1 and S2?
(ii) How will the electric flux through the sphere S1 change, if a medium of dielectric constant 6 is introduced in the space inside S1 in place of air?
(i)
(ii) If a medium of dielectric constant k is introduced then,
Using Gauss's theorem,
i.e,
Given,
Electric field, E =
Torque ,
Since the weight of an oil drop is balanced in an electric field we will have
where, q is the charge on the oil drop.
Consider the equilibrium of sphere A.
Following forces act on the sphere A.
(i) Force F of repulsion on A due to B.
(ii) Weight mg acting vertically downwards.
(iii) Tension T in the string towards the point of suspension O.
Resolving the tension T into two rectangular components:
For equilibrium of A,
and
Dividing,
But