Two long parallel wires separated by 4.0 mm each carry a current of 24 A. These two currents are in the same direction. What is the magnitude of the magnetic field at a point that is between the two wires and 1.0 mm from one of the two wires?
A) 4.8 mT
B) 6.4 mT
C) 3.2 mT
D) 9.6 mT
E) 5.3 mT

Question

Quizplus · Accepted Answer

Using the formula for the magnetic field between two parallel wires with currents in the same direction, we have:
$$B = \frac{\mu_0I}{2\pi d}$$
where $\mu_0$ is the permeability of free space, $I$ is the current, and $d$ is the distance between the wires. Plugging in the given values, we get:
$$B = \frac{(4\pi 	imes 10^{-7} T \cdot m/A)(24 A)}{2\pi (4.0 	imes 10^{-3} m - 1.0 	imes 10^{-3} m)} = 3.2 	ext{ mT}$$
Therefore, the answer is choice C.

Two Long Parallel Wires Separated by 4