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. |
An iron rod of susceptibility \(599\) is subjected to a magnetising field of \(1200~\text{A m}^{-1}\). The permeability of the material of the rod is:\(\left(\mu_0 = 4 \pi\times 10^{-7}~\text{T m A}^{-1}\right)\)
1. \(8.0\times 10^{-5}~\text{T m A}^{-1}\)
2. \(2.4\pi\times 10^{-5}~\text{T m A}^{-1}\)
3. \(2.4\pi\times 10^{-7}~\text{T m A}^{-1}\)
4. \(2.4\pi\times 10^{-4}~\text{T m A}^{-1}\)
i. | \(A\) is feebly repelled. | ii. | \(B\) is feebly attracted. |
iii. | \(C\) is strongly attracted. | iv. | \(D\) remains unaffected. |
1. | \(C\) is of a diamagnetic material. |
2. | \(D\) is of a ferromagnetic material. |
3. | \(A\) is of a non-magnetic material. |
4. | \(B\) is of a paramagnetic material. |
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. |
A short bar magnet of magnet moment \(0.4\) is placed in a uniform magnetic field of \(0.16\) . The magnet is in stable equilibrium when the potential energy is:
1. \(0.064\) J
2. \(-0.064\) J
3. zero
4.\(-0.082\) J
A solenoid has a core of material with relative permeability \(400.\) The windings of the solenoid are insulated from the core and carry a current of \(2\) A. If the number of turns is \(1000\) per metre, the magnetic field intensity \(H\) is:
1. \(2\times10^2\) A/m
2. \(2\times10^3\) A/m
3. \(2\) A/m
4. \(20\) A/m
A solenoid has a core of material with relative permeability \(400.\) The windings of the solenoid are insulated from the core and carry a current of \(2~\text{A}\). If the number of turns is \(1000\) per metre, the magnetising field \(B\) is:
1. | \(10~\text{T}\) | 2. | \(1~\text{T}\) |
3. | \(0.1~\text{T}\) | 4. | \(2~\text{T}\) |
A solenoid has a core of material with relative permeability \(400.\) The windings of the solenoid are insulated from the core and carry a current of \(2~\text{A}\). If the number of turns is \(1000\) per metre, the magnetizing current \(I_m\) is:
1. \(746~\text{A}\)
2. \(700~\text{A}\)
3. \(729~\text{A}\)
4. \(794~\text{A}\)
A domain in ferromagnetic iron is in the form of a cube of side length \(1\) µm. The maximum possible dipole moment is:
[The molecular mass of iron is \(55\) g/mole and its density is \(7.9\) g/cm3. Assume that each iron atom has a dipole moment of \(9.27\times 10^{-24}\) Am2]
1. \(8.0\times10^{-13}\) Am2
2. \(8.0\times10^{-12}\) Am2
3. \(7.0\times10^{-13}\) Am2
4. \(7.0\times10^{-12}\) Am2