Question

A straight wire carrying a current I₂ runs along the axis of a circular current I₁ (Fig.). What is the force of interaction between the currents?

Answer 1

Answer:  F = 0.

Explanation:

The magnetic lines of force due to the current I₂ form concentric circles. The current I₁ flows along one of these lines of force. Therefore the magnetic field, will not act on current I₁ All elements of the conductor carrying the current I₂ also coincide with the axial lines of force of the magnetic field due to I₁ The magnetic field due to I₁ will therefore not exert any force on current I₂.