A rectangular loop of sides 15 cm and 10 cm. carrying a current of 1 A, is placed with its longer side parallel to long straight wire carrying a current of 2 A placed at distance of 2 cm. The net force experience by the loop is:

Question

Question

This question was previously asked in

AAI ATC Junior Executive 2015 Official Paper (Shift 1)

Answer 1

Concept:

The magnetic field produced by a steady current flowing in a very long straight wire. The magnitude of the magnetic field is

Parallel wires carrying currents will exert forces on each other.
Each wire produces a magnetic field, which influences the other wire.
When the currents in both wires flow in the same direction, then the force is attractive.
When the currents flow in opposite directions, then the force is repulsive.

The force exerted on wires can be given by:

Calculation:

Given:

r1 = 2 cm, r2 = 10 + 2 = 12 cm, I₁ = 2A, I₂ = 1A

Force (F₁) on AB = (Direction is towards XY)

Force (F₂) on CD = (Direction is away from XY)

Net Force on the loop

= F₁ - F₂ = (30 – 5) × 10^-7 N = 25 × 10^-7 N