List of top Physics Questions on Types of Magnets

The magnetic moment of an iron bar is \( M \). It is now bent in such a way that it forms an arc section of a circle subtending an angle of \( 60^\circ \) at the centre. The magnetic moment of the arc section is

On both sides of a magnetic needle, two short magnets $A$ and $B$ are placed on the same horizontal line which is perpendicular to the magnetic meridian. The south poles of $A$ and $B$ are facing each other, which are $10\text{ cm}$ and $20\text{ cm}$ respectively from the magnetic needle. If the needle remains undeflected, the ratio of the magnetic moment of $A$ to that of $B$ is:

If a bar magnet is cut along the dotted line as shown in the figure and the two pieces are held separated by a small distance as they are, then

A bar magnet has a magnetic moment equal to \(5 \times 10^{-5}\,\text{Wb}\cdot\text{m}\). It is suspended in a magnetising field equal to \(8\pi \times 10^{-4}\,\text{A}\cdot\text{m}^{-1}\). The magnet vibrates with a period \(15\,\text{s}\). The moment of inertia of the magnet is:

The time period of a freely suspended magnet is \(4\,s\). If it is broken in length into two equal parts and one part is suspended in the same way, then the time period will be: