¿Questions About Magnetism
How does magnetism work?
You'll find a good introduction to magnetism here: Wikipedia entry on magnetism
¿What does remanence mean?
Remanence Br is a measurement for the magnetic induction or magnetic flux density that, after successful magnetisation, remains in the magnet. Simply said: the higher this value is, the "stronger" the magnet.
T (Tesla) is used as the unit of measurement for magnetic induction and, respectively, magnetic flux density. The unit of measurement previously used was G (Gauss). 1 Tesla = 10000 Gauss.
¿What does coercive field strength mean?
Coercive field strength Hc describes the force that is necessary to completely demagnetise a magnet. Simply said: the higher this number is, the better a magnet retains its magnetism when exposed to an opposing magnetic field.
There are differences between the coercive field strength bHc of flux density and the coercive field strength jHc of polarisation. If a magnet is exposed to a demagnetising field strength of bHc, the magnetic flux density in the magnet disappears. The magnet itself is still magnetic, but the flux density that the magnet generated is contrarily exactly the same size as the flux density of the demagnetised field, so that the two cancel each other out. The magnet only loses its magnetic polarisation, and thus its total magnetism, by a demagnetising field strength of jHc..
The standard unit of measurement used for a magnetic field strength is A/m (Ampere per metre). You will also often see the old standard measurement, Oe (Oersted).
What does maximum energy product mean?
The maximum energy product is a measurement for the maximum amount of magnetic energy stored in a magnet. It concerns the product maximally attainable with a material made out of flux density B and field strength H.
The standard unit of measurement is kJ/m³ (Kilojoule per cubic meter) or MGOe (Mega-Gauss-Oersted).
You can use either a small magnet with a higher energy product or a large magnet with a smaller energy product for the same use.
¿How can I find out which is the north pole of the magnet? ?
The north pole of a magnet is the pole that - as long as the magnet can spin freely - points towards the north. You can demonstrate this by putting multiple S-05-25-N magnets together and hanging them from a piece of string. Since the opposite poles attract each other, it follows that the north pole of the world is actually a magnetic south pole - and this is indeed so.
Furthermore, you can determine the north pole of a magnet with the help of a compass: The needle end, which normally points towards the south, will be pulled by the north pole of the magnet.