Q. No.| 1. | \(9~\text{gauss}\) | 2. | \(4~\text{gauss}\) |
| 3. | \(36~\text{gauss}\) | 4. | \(4.5~\text{gauss}\) |
1. \(3 \times 10^{-5}\) N-m
2. \(30\) N-m
3. \(3 \times 10^{-3}\) N-m
4. \(3 \times 10^{-2}\) N-m
A solenoid of cross-sectional area \(2\times 10^{-4}~\text{m}^2\) and \(1000\) turns placed with its axis at \(30^\circ\) with an external field of \(800~\text{G}\) experiences a torque of \(0.016~\text{Nm}.\) The current flowing through the solenoid is:
1. \(2~\text{A}\)
2. \(4~\text{A}\)
3. \(1~\text{A}\)
4. \(5~\text{A}\)
| 1. | \(M\) | 2. | \(\dfrac{M\pi}{2}\) |
| 3. | \( \dfrac{M}{2\pi}\) | 4. | \(\dfrac{2M}{\pi}\) |
| 1. | \(\dfrac{3 M}{\pi}\) | 2. | \(\dfrac{4M}{\pi}\) |
| 3. | \(\dfrac{ M}{\pi}\) | 4. | \(\dfrac{2 M}{\pi}\) |
1. \(1~\text J\)
2. \(2~\text J\)
3. \(3~\text J\)
4. \(4~\text J\)
A short bar magnet placed with its axis at \(30^{\circ}\) with an external field of \(800~\text{G}\) experiences a torque of \(0.016~\text{N-m}\). What is the work done in moving it from its most stable to the most unstable position?
1. \(0.036~\text{J}\)
2. \(0.016~\text{J}\)
3. \(0.064~\text{J}\)
4. \(0\)
| 1. | \(128\pi^2\) | 2. | \(50\pi^2\) |
| 3. | \(1280\pi^2\) | 4. | \(5\pi^2\) |
Four small identical bar magnets, each of magnetic dipole moment \(M\), are placed on the vertices of a square of side \(a\) such that the diagonals of the square coincide with the perpendicular bisectors of the respective magnets. The net magnetic field at the centre of the square is:
1. zero
2. \(\dfrac{\mu_{0}}{\sqrt{2 \pi}} \dfrac{M}{a^{3}}\)
3. \(\dfrac{2 \sqrt{2} \mu_{0}}{\pi} \cdot \dfrac{M}{a^{3}}\)
4. \(\dfrac{\mu_{0}}{\pi} \cdot \dfrac{M}{a^{3}}\)
| 1. | \(B^{-3}\) | 2. | \(B^{-2}\) |
| 3. | \(B^{-1/2}\) | 4. | \(B^{-1/3}\) |
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