Magnetism and Matter

In a magnetic dipole, two equal and opposite magnetic poles are kept at a small distance. In concept, it is equal to an electric dipole. The magnetic dipole moment (M) represents the strength and orientation of the magnetic dipole and it is a vector quantity. The formula is: M = m * 2l. Here m represents the pole strength and 21 shows the distance between the poles. The direction of M is from the south pole to the north pole of the magnet, and its SI unit is A·m².

The region around a moving electric charge or a magnetic material where the force of magnetism acts is called the magnetic field. The magnetic field lines are used to represent the strength and direction of the magnetic field and these are imaginary lines. The density of these lines shows the field strength. The magnetic field emerges from the magnet's north pole and enters the south pole. The magnetic field is stronger for the closer lines. These lines always form closed loops and never intersect each other. It differentiates it from the electric field which starts or ends on charges.