Q. No.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.
| (i) | \(A\) is feebly repelled. | (ii) | \(B\) is feebly attracted. |
| (iii) | \(C\) is strongly attracted. | (iv) | \(D\) remains unaffected. |
Which one of the following is true?
| 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. |
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 magnetizing field of \(1200~\text{A m}^{-1}.\) The permeability of the material of the rod is:
\((\mu_0 = 4 \pi\times 10^{-7}~\text{T mA}^{-1})\)
1. \(8.0\times 10^{-5}~\text{T mA}^{-1}\)
2. \(2.4\pi\times 10^{-5}~\text{T mA}^{-1}\)
3. \(2.4\pi\times 10^{-7}~\text{T mA}^{-1}\)
4. \(2.4\pi\times 10^{-4}~\text{T mA}^{-1}\)
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 \(2~\text A.\) If the number of turns is \(1000\) per metre, the magnetic field intensity \(H\) is:
1. \(2\times10^2~\text{A/m}\)
2. \(2\times10^3~\text{A/m}\)
3. \(2~\text{A/m}\)
4. \(20~\text{A/m}\)
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 \(1~\mu\text m.\) The maximum possible dipole moment is:
[The molecular mass of iron is \(55~\text{g/mole}\) and its density is \(7.9~\text{g/cm}^3.\) Assume that each iron atom has a dipole moment of \(9.27\times 10^{-24}~\text{Am}^2\)]
1. \(8.0\times10^{-13}~\text{Am}^2\)
2. \(8.0\times10^{-12}~\text{Am}^2\)
3. \(7.0\times10^{-13}~\text{Am}^2\)
4. \(7.0\times10^{-12}~\text{Am}^2\)
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