Question

Torque on a Dipole in a Uniform Electric Field When electric dipole is placed in uniform electric field, its two charges experience equal and opposite forces, which cancel each other and hence net force on electric dipole in uniform electric field is zero. However these forces are not collinear, so they give rise to some torque on the dipole. Since net force on electric dipole in uniform electric field is zero, so no work is done in moving the electric dipole in uniform electric field . however some work is done in rotating the dipole against the torque acting on it​

Answer 1

Answer:

The electric field generated by the point charge is non-uniform which varies as ∝

r

2

1

. For the diplole the electric field acting on the two charges never be equal. Hence the net electric field on the dipole cannot be zero. Thus electric force acting on the the two charges will never cancel each other.

For the torque acting on the dipole, first remember that in uniform electric field the torque becomes zero when the dipole becomes aligned to the electric field direction because the forces acting on the two charges is same but in case of non uniform electric field by point charge as the force acting on the charges are not equal and hence the torque acting would never be zero even when the dipole is aligned to electric field.