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

0.25 m

Step-by-step explanation:

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

`B=(\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=(\mu_0 I)/(2 \pi B)=((4\pi \cdot 10^(-7))(5.0 A))/(2\pi(4\cdot 10^(-6) T))=0.25 m`