An arrangement of three parallel straight wires placed perpendicular to the plane of paper carrying the same current in the same direction is shown in the figure. The magnitude of force per unit length on the middle wire \(B\) is given by:
1. | \(\frac{\mu_0i^2}{2\pi d}\) | 2. | \(\frac{2\mu_0i^2}{\pi d}\) |
3. | \(\frac{\sqrt{2}\mu_0i^2}{\pi d}\) | 4. | \(\frac{\mu_0i^2}{\sqrt{2}\pi d}\) |