Question

Two long, straight wires are parallel and 20 cm apart. One carries a current of 2.5 A, the other a current of 5.6 A. (a) If the two currents flow in opposite directions, what is the magnitude (in N/m) and direction of the force per unit length of one wire on the other? magnitude N/m direction --Select- (b) What is the magnitude (in N/m) and direction of the force per unit length if the currents flow in the same direction? magnitude N/m direction ----Select-

Answer 1

a] We know that force between current carrying wire

Force per length = u0i1i2/2pi r = 2e-7*2.5*5.6/0.20 = 0.000014 N/m

direction = away from each other because current is in opposite direction.

b] Force per length = u0i1i2/2pi r = 2e-7*2.5*5.6/0.20 = 0.000014 N/m

direction = towards each other because current is in same direction.