A bar magnet of magnetic moment $M$ is placed at right angles to a magnetic induction $B.$ If a force $F$ is experienced by each pole of the magnet, the length of the magnet will be

Two bar magnets with magnetic moments $ 2 M $ and $M$ are fastened together at right angles to each other at their centres to form a crossed system, which can rotate freely about a vertical axis through the centre. The crossed system sets in earth’s magnetic field with magnet having magnetic moment $2M $ making and angle  $ \theta $ with the magnetic meridian such that

A vibration magnetometer consists of two identical bar magnets placed one over the other such that they are perpendicular and bisect each other. The time period of oscillation in a horizontal magnetic field is ${2^{5/4}}$ $seconds$. One of the magnets is removed and if the other magnet oscillates in the same field, then the time period in seconds is

The magnetic field at a point $x $ on the axis of a small bar magnet is equal to the field at a point $  y  $ on the equator of the same magnet. The ratio of the distances of $x$ and $y$  from the centre of the magnet is

The magnetic moment of a magnet of length $10\, cm$  and pole strength $ 4.0\, Am$  will be……$A{m^2}$