Magnetism And Matter - Electromagnetism - Physics Previous Year Questions

In a permanent magnet at room temperature

A magnetic needle has a magnetic moment of \(5 \times 10^{-2} \mathrm{~Am}^2\) and moment of inertia \(8 \times 10^{-6} \mathrm{~kgm}^2\). It has a period of oscillation of \(2 \mathrm{~s}\) in a magnetic field \(\mathbf{B}\). The magnitude of magnetic field is approximately?

A circular current loop of magnetic moment \(M\) is in a arbitrary orientation in an external uniform magnetic field \(\mathbf{B}\). The work done to rotate the loop by \(30^{\circ}\) about an axis perpendicular to its plane is

In a permanent magnet at room temperature

A paramagnetic sample shows a net magnetisation of \(8 \mathrm{Am}^{-1}\) when placed in an external magnetic field of \(0.6 \mathrm{~T}\) at a temperature of \(4 \mathrm{~K}\). When the same sample is placed in an external magnetic field of \(0.2 \mathrm{~T}\) at a temperature of \(16 \mathrm{~K}\), the magnetisation will be

Earth's magnetic field always has a horizontal component except at

The Curie temperature of cobalt and iron are \(1400 \mathrm{~K}\) and \(1000 \mathrm{~K}\) respectively. At \(T=1600 \mathrm{~K}\), the ratio of magnetic susceptibility of cobalt to that of iron is

The horizontal component of Earth's magnetic field at a place is \(3 \times 10^{-5} \mathrm{~T}\). If the dip at that place is \(45^{\circ}\), the resultant magnetic field at that place is

Magnetic susceptibility of Mg at 300 K is $1.2 \times 10^{-5}$. What is its susceptibility at $200 \mathrm{~K} ?$

Magnetic hysterisis is exhibited by ............ magnetic materials

Which of the following statements is true in respect of diamagnetic susbtances?