The magnetic susceptibility \(\chi\) of a diamagnetic material depends on absolute temperature \(T\) as:
1. \(\chi \propto T\)
2. \(\chi \propto \frac{1}{T}\)
3. \(\chi \propto T^0\)
4. \(\chi \propto \frac{1}{\sqrt{T}}\)
The magnetic lines of force inside a bar magnet are:
1. | from south to the north pole. |
2. | from north to the south pole. |
3. | not present. |
4. | intersecting each other. |
The material which is used to make permanent magnet has:
1. | High retentivity, low coercivity |
2. | Low retentivity, low coercivity |
3. | Low retentivity, high coercivity |
4. | High retentivity, high coercivity |
Which of the following is not dimensionless?
(where symbols stand for their usual meanings in magnetism)
1. \(\frac{I}{H}\)
2. \(\frac{B}{\mu_0H}\)
3. \(\mu_r\)
4. \(\frac{\mu_r B}{H}\)
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. | \(4M\) |