Question

A circular coil of radius 2.0 cm has 500 turns and carries a current of 1.0 A. Its axis makes an angle of 30° with the uniform magnetic field of magnitude 0.40 T that exists in the space. Find the torque acting on the coil.

Answer 1

Given:
No. of turns of the coil, n = 500
Magnetic field intensity, B = 0.40 T = 4 × 10⁻¹ T
Radius of the coil, r = 2 cm = 2 × 10⁻² m
Magnitude of current, i = 1 A
Angle between the area vector and magnetic field, θ = 30°
Torque acting on the coil,
τ = niABsinθ
Here, A is the area of the coil.
τ = 500 × 1 × 3.14 × 4 × 10⁻⁴ ×4×10⁻¹ × $\frac{1}{2}$
= 12.56 × 10⁻²
= 0.1256 = 0.13 N-m