Three parallel wires of length l each carry current Iin the same direction. They’re positioned at the vertices of an equilateral triangle of side a, and oriented perpendicular to the triangle.

Find an expression for the magnitude of the force on each wire.

Express your answer in terms of the variables I, l, a, and appropriate constants.

Explanation:

To solve this problem we can use the expression for the force between two wires with currents I1 and I2, at a distance of r.

where L is the length of the wires. Wires feel the same force and the currents are in the same direction.

For our problem the three wires the force is the same. By taking into account that the distance among them is a we have

and the force on on of the wire is the sum of the effects of the others

where we have taken r=a (wires are equidistant in a equilateral triangle)and L=l for our problem

I hope this is useful for you

regards