Question

An electric dipole with dipole moment 4 × 10–9 C m is aligned at 30° with the direction of a uniform electric field of magnitude 5 × 104 NC–1. Calculate the magnitude of the torque acting on the dipole.

Answer 1

Answer:

Torque acting on the dipole is given by

τ = PEsinΦ

Where P is dipole moment

E is the Electric field

Φ is the angle between dipole moment and electric field.

Given, P = 4 × 10⁻⁹ Cm

E = 5 × 10⁴ N/C

Φ = 30°

∴ τ = 4 × 10⁻⁹ × 5 × 10⁴ sin30°

= 4 × 5 × 10⁻⁵ × 1/2

= 10⁻⁴ Nm

Hence, torque acting on dipole is 10⁻⁴ Nm

Answer 2

Dipole moment, |p| = 4 × 10-9 Cm, θ = 30,

E = 5 × 104 N/C

We know that,

Torque = p E sinθ

Torque = (4 × 10‒9) (5 ×104) (sin30o)

Torque = 10-4 Nm