An electric dipole of moment ‘p’ is placed in an electric field of intensity ‘E’. The dipole acquires a position such that the axis of the dipole makes an angle θ with the direction of the field. Assuming that the potential energy of the dipole to be zero when = 90⁰, the torque and the potential energy of the dipole will respectively be:

Options

(a) p E sin θ, – p E cos θ
(b) p E sin θ, – 2 p E cos θ
(c) p E sin θ, p E cos θ
(d) p E cos θ, – p E sin θ

Correct Answer:

p E sin θ, – p E cos θ

Explanation:

The torque on the dipole is given as ? = p E sin θ. The potential energy of otghe dipole in the electric field is given as U = – p E cos θ.