Two parallel wires, 4 cm apart, carry currents of 2 A and 4 A respectively, in opposite directions.The force per unit length of one wire on the other is: A)1 *10^-3 N/m, repulsive B)1 *10^-3 N/m, attractive C)4 * 10^-5 N/m, repulsive D)4 * 10^-5 N/m, attractive E)none of these

Question

Quizplus · Accepted Answer

The force per unit length between the two wires is given by the equation $F = \frac{\mu_0 I_1 I_2}{2\pi d}$, where $\mu_0$ is the permeability of free space, $I_1$ and $I_2$ are the currents in the wires, and $d$ is the distance between the wires. Substituting the given values, we get:

$F = \frac{(4\pi 	imes 10^{-7}	ext{ T}\cdot	ext{m}/	ext{A})(2	ext{ A})(4	ext{ A})}{2\pi(0.04	ext{ m})} = 4	imes 10^{-5}$ N/m

Since the currents are flowing in opposite directions, the force will be repulsive, pushing the wires away from each other. Therefore, the best choice is (C).

Two Parallel Wires, 4 Cm Apart, Carry Currents of 2