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. \(7.0\times10^{-12}~\text{Am}^2\)
1. | increased |
2. | decreased |
3. | unchanged |
4. | fluctuating with time: first increasing and then decreasing |
1. | increases |
2. | decreases |
3. | remains unchanged |
4. | decreases first and then increases |
1. | all the domains grow in size. |
2. | all the domains shrink in size. |
3. | some domains grow in size, others shrink. |
4. | domains rotate in the magnetic field. |
(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. |
1. | attractive. |
2. | repulsive. |
3. | zero. |
4. | any of the above depending on the external field \(B\) and the sample separation. |