$A$ short bar magnet has a magnetic moment of $0.48 \, J \, T^{-1}$. The magnitude of magnetic field at a point at $10 \, cm$ distance from the centre of the magnet on its axis is

Two identical thin bar magnets each of length $l$ and pole strength $m$ are placed at right angles to each other with the north pole of one touching the south pole of the other. The magnetic moment of the system is:

Three identical bar magnets each of magnetic moment $M$ are placed in the form of an equilateral triangle as shown. The net magnetic moment of the system is

Write a brief history of magnets.

Two similar bar magnets $P$ and $Q$,each of magnetic moment $M$,are taken. If $P$ is cut along its axial line and $Q$ is cut along its equatorial line,all the four pieces obtained have:

The magnetic dipole moment of a short magnetic dipole at a distant point along the equator of the magnet has a magnitude of $X$ in $SI$ units. If the distance between the point and the magnet is halved,then the magnitude of the dipole moment will be