A current of 1.41 A in a long, straight wire produces a magnetic field of 5.61 uT at a certain distance from the wire. Find
this distance.

0.050 m

Explanation:

The strength of the magnetic field produced by a current-carrying wire is given by

where

is the vacuum permeability

I is the current in the wire

r is the distance from the wire

And the magnetic field around the wire forms concentric circles, and it is tangential to the circles.

In this problem, we have:

(current in the wire)

(strength of magnetic field)

Solving  for r, we find the distance  from the wire:

gets less

the answer is 100. i just did this lesson and got a 100% on it. : )

-fishtank