A coil suspended freely in a radial magnetic field rotates through 30�

1.	A coil suspended freely in a radial magnetic field rotates through 30° when a current of 30 A is passed through it. Through what angle will it rotate if the current is doubled and the magnetic induction is halved?
Answer» The angle of rotation, θ ∝ IB (in the usual notation) As I₂B₂ = (2I₁) \(\left(\cfrac{B_1}2 \right)\) = I₁B₁, the angle of rotation will be the same, i.e., 30°.

A coil suspended freely in a radial magnetic field rotates through 30° when a current of 30 A is passed through it. Through what angle will it rotate if the current is doubled and the magnetic induction is halved?

Answer»

The angle of rotation, θ ∝ IB (in the usual notation)

As I₂B₂ = (2I₁) \(\left(\cfrac{B_1}2 \right)\)

= I₁B₁,

the angle of rotation will be the same, i.e., 30°.