Question

Question 1.10: 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 × 10 4 N C −1 . Calculate the magnitude of the torque acting on the dipole.

Class 12 - Physics - Electric Charges And Fields Electric Charges And Fields Page-46

Answer 1

Hey mate!

Here's your answer!!

Electric dipole moment, p = 4 × 10−9 C m
Angle made by p with a uniform electric field, θ = 30°
Electric field, E = 5 × 104 N C−1
Torque acting on the dipole is given by the relation, τ = pE sinθ

= 4×10^-9×5×10^4×sin30
= 20×10^-5×1/2
=10^-4 Nm

Therefore, the magnitude of the torque acting on the dipole is 10−4 N m.

$hope \: it \: helps \: you.$

Answer 2

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