Awire with a current of 3.40 a is to be formed into a circular loop of one turn. if the required value of the magnetic field at the center of the loop is 20 µt, what is the required radius?

0.107 m

Explanation:

The magnetic field at the center of a current-carrying loop is given by

where

is the vacuum permeability

I is the current

r is the radius of the loop

In this problem we have

I = 3.40 A is the current in the loop

is the magnetic field at the centre of the loop

So, solving the formula for r we find

this could be newton#'s law of cooling. the cooling curve is exponential