Two pith balls carrying equal charges are suspended from a common point by strings of equal length, the equilibrium separation between them is r. Now the strings are rigidly clamped at half the height. The equilibrium separation between the balls now become:

For an electric dipole in a non-uniform electric field with dipole moment parallel to direction of the field, the force F and torque τ on the dipole respectively are ___________.
Fill in the blank with the correct answer from the options given below.

Two charged particles, placed at a distance d apart in vacuum, exert a force F on each other. Now, each of the charges is doubled. To keep the force unchanged distance between the charges should be changed to _____________.
Fill in the blank with the correct answer from the options given below.

An electric dipole is placed at an angle of 30° with an electric field of intensity . It experiences a torque equal to 4 Nm. Calculate the magnitude of charge on the dipole, if the dipole length is 2 cm.

If over a surface, then :

Two identical charged spheres suspended from a common point by two massless strings of lengths l, are initially at a distance d(d < < l) apart because of their mutual repulsion. The charges begin to leak from both the spheres at a constant rate. As a result, the spheres approach each other with a velocity υ. Then υ varies as a function of the distance x between the spheres, as

A dipole is placed in an electric filed as shown. In which direction will it move?

In a region, the potential is represented by V(x, y, z) = 6x – 8xy – 8y + 6yz, where V is in volts and x, y, z are in metres. The electric force experienced by a charge of 2 coulomb situated at point (1, 1, 1) is :-

An electric dipole is placed as shown in the figure.
The electric potential (in 10² V) at point P due to the dipole is

For an electric dipole in a non-uniform electric field with dipole moment parallel to direction of the field, the force F and torque τ on the dipole respectively are ___________.
Fill in the blank with the correct answer from the options given below.