| (I) | at two adjacent vertices \(A,B\) |
| (II) | at two points \(A,C\) at the ends of a diagonal. |
| 1. | \(2\) | 2. | \(\dfrac12\) |
| 3. | \(\dfrac{1}{\sqrt2}\) | 4. | \(1\) |
| 1. | a circle |
| 2. | a straight line |
| 3. | a circle or a straight line |
| 4. | a circle, a straight line, or a parabola |
| 1. | \(\dfrac{\mu_{0} i}{2 \pi d}\) | 2. | \(\dfrac{2\mu_{0} i}{2 \pi d}\) |
| 3. | \(\dfrac{\sqrt 3\mu_{0} i}{2 \pi d}\) | 4. | zero |
| 1. | \(\Large\frac{qBd}{2}\) | 2. | \(qBd\) |
| 3. | \(2qBd\) | 4. | \(\Large\frac{qBd}{4}\) |
| 1. | \(\dfrac{K}{a}\) | 2. | \(\dfrac{K}{b}\) |
| 3. | \(\dfrac{K}{a-b}\) | 4. | \(\dfrac{K}{a+b}\) |
Two insulated current carrying wires lie along the \(x\) and the \(y\text-\)axis in the \(xy\text-\)plane, carrying identical currents \(I\). The magnetic field at the point \((d,-d)\) is:

| 1. | \(\text{Zero}\) | 2. | \(\dfrac{\mu_0I}{\pi d}\) |
| 3. | \(\sqrt2\cdot \dfrac{\mu_0I}{2\pi d}\) | 4. | \(\dfrac{\mu_0I}{2\pi (\sqrt2 d)}\) |
| 1. | \(\pi du\) | 2. | \(2\pi du\) |
| 3. | \(\Large\frac{\pi du}{2}\) | 4. | \(\Large\frac{\pi du}{4}\) |
| 1. | \(q\Phi\) | 2. | \(\dfrac{q\Phi}{2\pi}\) |
| 3. | \(\pi q\Phi\) | 4. | \(\dfrac{q\Phi}{\pi}\) |
| 1. | \(\dfrac{5}{\sqrt3r}\) | 2. | \(\dfrac{5}{\sqrt3\pi r}\) |
| 3. | \(\dfrac{5}{r}\) | 4. | \(\dfrac{5}{\pi r}\) |