Magnetic Effects of Current & Magnetism · JEE Main previous year questions

2016 1 question

1. Q462016 · 3 Apr 2016 · Shift 1

   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 fields at the centres of the circle and square respectively, then the ratio $\frac{B_A}{B_B}$ is:

   1. A.$\frac{{\pi }^2}{16}$
   2. B.$\frac{{\pi }^2}{8\sqrt{2}}$
   3. C.$\frac{{\pi }^2}{8}$
   4. D.$\frac{{\pi }^2}{16\sqrt{2}}$
   Show answer

   Answer: B