A wire of length l is in the form of a circular loop A of one turn. This loop is reshaped into loop B of three turns. Find the ratio of the magnetic…

\[\begin{aligned} & B=\frac{\mu_{o} N I}{2 r} \\ & l=2 \pi r ; \quad 2 \pi r_{A}=3\left(2 \pi r_{B}\right) \\ & r_{B}=\frac{r_{A}}{3} \\ & \frac{B_{A}}{B_{B}}=\frac{\mu_{o} N_{A} I}{2 r_{A}} \times \frac{2 r_{B}}{\mu_{0} N_{B} I} \end{aligned} \] &