Question

IN a physics lab, a student discovers that the magnitude of the magnetic field at a certain distance from a long wire is 4.0μT. If the wire carries a current of 5.0 A, what is the distance of the magnetic field from the wire?

Answer 1

Answer:

0.25 m

Explanation:

The intensity of the magnetic field around a current-carrying wire is given by:

$B=\frac{\mu_0 I}{2 \pi r}$

where

where

$\mu_0 = 4\pi \cdot 10^{-7}Tm/A$ is the permeabilty of free space

I is the current

r is the distance from the wire

In this problem, we know:

$B=4 \mu T=4 \cdot 10^{-6} T$ is the magnetic field

$I=5.0 A$ is the current in the wire

Re-arranging the equation, we can find the distance of the field from the wire:

$r=\frac{\mu_0 I}{2 \pi B}=\frac{(4\pi \cdot 10^{-7})(5.0 A)}{2\pi(4\cdot 10^{-6} T)}=0.25 m$