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. T/2
3. 2/T
4. T
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. | \(\frac{3M}{\pi}\) | 2. | \(\frac{2M}{l\pi}\) |
3. | \(\frac{M}{ 2}\) | 4. | \(M\) |
Due to a small magnet, the intensity at a distance \(x\) in the end-on position is \(9~\text{gauss}\). What will be the intensity at a distance \(\frac{x}{2}\) on equatorial position?
1. \(9~\text{gauss}\)
2. \(4~\text{gauss}\)
3. \(36~\text{gauss}\)
4. \(4.5~\text{gauss}\)
A long magnetic needle of length 2L, magnetic moment M and pole strength m units is broken into two pieces at the middle. The magnetic moment and pole strength of each piece will be:
1.
2.
3.
4. M, m
1. | \(\frac{MB}{F}\) | 2. | \(\frac{BF}{M}\) |
3. | \(\frac{MF}{B}\) | 4. | \(\frac{F}{MB}\) |
The magnetic moment of a bar magnet of length \(L\) and area of cross-section \(A\) is \(M\). If the magnet is cut into four identical parts each of length \(L\) and area of cross-section \(\frac{A}{4}\), then magnetic moment of each part is:
1. | \(\frac{M}{4}\) | 2. | \(\frac{M}{2}\) |
3. | \(M\) | 4. | \(4M\) |
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.
2.
3. Zero
4.