The formula for the area of a circle is $A = \pi r^2$, where $r$ is the radius of the circle. In this case, the radius of the wire is half of its diameter, so $r = 0.5 \times 1.0 \times 10^{-3} \, m = 0.5 \times 10^{-3} \, m$. Substituting this into the formula
Show more…