The hot and neutral wires supplying DC power to a light-rail commuter train carry 700 A and are separated by 70.0 cm. What is the magnitude (in N) of the force between 30.0 m of these wires?

4.197 N

Explanation:

current through the wires I = 700 A

distance between wires r = 70 cm = 0.7 m

length of each wire L = 30 m

force per unit length on the wires is given as

=

where u = permeability of vacuum = 1.256 m-kg-

F =  

F =   = 4.197 N