Question

Two long, straight wires carry equal currents of 0.56 A. The two wires are parallel to each other and carry parallel currents. What is the magnetic field at a midpoint between the two wires, if the wires are 0.5 cm apart? The magnetic field of a long, straight wire is: B=(μ_0 i)/2πr What is the force per unit length of one of the wires in number 2 on the other?

Answer 1

Magnetic field at the midpoint will be zero as current in the wires are in same direction which will cancel each others field.

Force per unit length = u0 i1*i2/2pir

= 2e-7*0.56^2/0.005

= 0.0000125 N/m answer