A long cylindrical wire (radius = 2.0 cm) carries a current of 40 A that is uniformly distributed over a cross section of the wire. What is the magnitude of the magnetic field at a point which is 1.5 cm from the axis of the wire?

Question

Quizplus · Accepted Answer

We can use the formula $B=\frac{\mu_0}{2\pi}\frac{I}{r}$ where $\mu_0$ is the permeability of free space, $I$ is the current, and $r$ is the distance from the axis of the wire. Plugging in the given values, we get:
$$B=\frac{\mu_0}{2\pi}\frac{40}{0.015}=0.30	ext{ mT}$$
Therefore, the correct answer is C.

A Long Cylindrical Wire (Radius = 2