Q. No.Figure shows two small identical magnetic dipoles \(a\) and \(b\) of magnetic moments \(M\) each, placed at a separation \(2d\), with their axes perpendicular to each other. The magnetic field at the point \(P\) midway between the dipoles is:
| 1. | \(\dfrac{2 \mu_{0} M}{4 \pi d^{3}}\) | 2. | \(\dfrac{\mu_{0} M}{4 \pi d^{3}}\) |
| 3. | zero | 4. | \(\dfrac{\sqrt{5}\mu_{0} M}{4\pi d^{3}}\) |
| 1. | equal pole strength |
| 2. | magnetic moment \(\frac{M}{4}\) |
| 3. | magnetic moment \(\frac{M}{2}\) |
| 4. | magnetic moment \(M\) |
The unit of pole strength is:
1. \(\text{Am}^2\)
2. \(\text{Am}\)
3. \(\frac{\text{A}^2}{\text{m}}\)
4. \(\frac{\text{A}^2}{\text{m}^2}\)
The following figures show the arrangement of bar magnets in different configurations. Each magnet has a magnetic dipole. Which configuration has the highest net magnetic dipole moment?
| 1. |  |
2. |  |
| 3. |  |
4. |  |
| 1. | \(\dfrac{MB}{F}\) | 2. | \(\dfrac{BF}{M}\) |
| 3. | \(\dfrac{MF}{B}\) | 4. | \(\dfrac{F}{MB}\) |
| 1. | \(9~\text{gauss}\) | 2. | \(4~\text{gauss}\) |
| 3. | \(36~\text{gauss}\) | 4. | \(4.5~\text{gauss}\) |
| 1. | \(\dfrac{3 M}{\pi}\) | 2. | \(\dfrac{4M}{\pi}\) |
| 3. | \(\dfrac{ M}{\pi}\) | 4. | \(\dfrac{2 M}{\pi}\) |
A bar magnet of length \(l\) and magnetic dipole moment \(M\) is bent in the form of an arc as shown in the figure. The new magnetic dipole moment will be:
| 1. | \(\dfrac{3M}{\pi}\) | 2. | \(\dfrac{2M}{l\pi}\) |
| 3. | \(\dfrac{M}{ 2}\) | 4. | \(M\) |
If a magnetic needle is made to vibrate in uniform field \(H\), then its time period is \(T\). If it vibrates in the field of intensity \(4H\), its time period will be:
| 1. | \(2T\) | 2. | \(\dfrac{T}{2}\) |
| 3. | \(\dfrac{2}{T}\) | 4. | \(T\) |
Two identical bar magnets are fixed with their centres at a distance \(d\) apart. A stationary charge \(Q\) is placed at \(P\) in between the gap of the two magnets at a distance \(D\) from the centre \(O\) as shown in the figure.
| 1. | zero. |
| 2. | directed along with \(OP\). |
| 3. | directed along with \(PO\). |
| 4. | directed perpendicular to the plane of the paper. |
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