Physics

Problem

Two identical wires A and B, each of length

l

, carry the same current

I

. Wire A is bent into a circle of radius

R

and wire B is bent to form a square of side

a

. If

B_A

and

B_B

are the values of magnetic field at the centres of the circle and square respectively, then the ratio

\frac{B_A}{B_B}

is: a.

\frac{\pi^2}{16}

\frac{\pi^2}{8\sqrt{2}}

\frac{\pi^2}{8}

\frac{\pi^2}{16\sqrt{2}}