Two similar coils of radius R are lying concentrically with their planes perpendicular to each other and carrying current I and 2 I respectively. What is the resultant magnetic field at the center?

$\frac{\mu_0 I}{2 R}$ $\frac{\mu_0 I}{2 R}$ $\frac{\sqrt{5} \mu_0 I}{2 R}$ $\frac{3 \mu_0 I}{2 R}$

$\frac{\sqrt{5} \mu_0 I}{2 R}$

The correct answer is Option (3) → $\frac{\sqrt{5} \mu_0 I}{2 R}$