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. \(10^{3}~\text{A/m}\)
2. \(10^{2}~\text{A/m}\)
3. \(10^{5}~\text{A/m}\)
4. \(10^{4}~\text{A/m}\)
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. |
If a magnetic dipole of dipole moment is rotated through an angle with respect to the direction of the magnetic field B, then work done is :
1. Bsin
2. B(1-sin)
3. Bcos
4. B(1-cos)
Magnetic permeability is maximum for
1. Diamagnetic substance
2. Paramagnetic substance
3. Ferromagnetic substance
4. Same for all three substances
The magnetic moment of a bar magnet shown in figure(i) is M.
If a hole is drilled through the magnet as shown in figure(ii), then the new magnetic moment of the magnet will be :
1. Equal to M
2. Less than M
3. More than M
4. Zero
When a substance is kept in a magnetic field, it gets repelled. Which of the following represents its susceptibility?
1. -0.0004
2. 0.0004
3. 1.000
4. -1.000
Magnetic susceptibility of a substance at \(27^{\circ}~\mathrm{C}\) is \(-0.00025\). Its magnetic susceptibility at \(127^{\circ}~\mathrm{C}\) is:
1. \(-0.000125\)
2. \(-0.0005\)
3. \(-0.00025\)
4. \(-0.00001\)
Magnetic induction at an axial point of a short magnet at a distance \(r\) from the centre of dipole is \(\vec B\). Its value at the equatorial point of the short magnet at the same distance from the centre of dipole is:
1. | \(-\vec B\) | 2. | \(\dfrac{\vec B}{2}\) |
3. | \(\vec B\) | 4. | \(\dfrac{-\vec B}{2}\) |