Question

A long horizontal wire P carries a current of 50 A. It is rigidly fixed. Another wire Q is placed directly above and parallel to P as shown in Figure 1 below. The weight per unit length of the wire Q is 0.025 N m-m and it carries a current of 25 A. Find the distance r of the wire Q from the wire P so that the wire Q remains at rest.

Answer 1

Given I₁ = 50 A, mg/L = 0.025 Nm^-1, I₂ = 25 A, r = ?

The  force between the wires will balance the weigh of wire Q.

Therefore,