The magnetic moment of a short dipole is \(100\) A-m2. The magnetic induction in vacuum at \(1\) m from the dipole on the axis of the dipole is:
1. | \(2\times10^{-5}~\text{T}\) | 2. | \(10^{-5}~\text{T}\) |
3. | \(2~\mu\text{T}\) | 4. | \(1~\mu\text{T}\) |
The magnetic moment of a magnet \((10 ~\text{cm}\times 4~\text{cm}\times1~\text{cm})\) is \(4 ~\text{Am}^2\). Its intensity of magnetisation is:
1. \(10^{3}\) A/m
2. \(10^{2}\) A/m
3. \(10^{5}\) A/m
4. \(10^{4}\) A/m
S.I. unit of intensity of magnetization is:
1. | Ampere-metre | 2. | Ampere-metre2 |
3. | Ampere/metre | 4. | Ampere/metre2 |
A ferromagnetic material is placed in an external magnetic field. The magnetic domains:
1. | must increase in size. |
2. | must decrease in size. |
3. | may increase or decrease in size. |
4. | disappear. |
1. | \(9~\text{gauss}\) | 2. | \(4~\text{gauss}\) |
3. | \(36~\text{gauss}\) | 4. | \(4.5~\text{gauss}\) |
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. | \(4M\) |
The possible value of magnetic susceptibility of a diamagnetic material can be:
1. \(-2.45\)
2. \(0.75\)
3. \(-0.5\)
4. \(1.67\)
The bar magnet \(A\) of magnetic moment \(M_A\) is found to oscillate at a frequency twice that of magnet \(B\) of magnetic moment \(M_B\) and the same moment of inertia when placed in a vibration magnetometer. We may say that:
1. | \(M_B=8M_A\) | 2. | \(M_A= 4M_B\) |
3. | \(M_A=8M_B\) | 4. | \(M_A=2M_B\) |
When a magnetic material is subjected to a very small magnetising force \(H,\) the intensity of magnetisation is proportional to:
1. | \(\frac{1}{\sqrt{H}} \) | 2. | \(\sqrt{H} \) |
3. | \(H \) | 4. | \(H^2\) |
The magnetization of a piece of iron or steel:
1. | depends on the strength of the magnetizing field. |
2. | depends on external conditions such as temperature. |
3. | cannot be done beyond the saturation point. |
4. | all of these. |