What is a Magnet ?
Magnet is an object or a device which gives off an external magnetic field. Basically, it applies a force over a distance on other magnets, electrical currents, beams of charge, circuits, or magnetic materials. Magnetism can even be caused by electrical currents.
While you might think of metal magnets such as the ones you use in class, there are many different types of magnetic materials. Iron (Fe) is an easy material to use. Other elements such as neodymium (Nd) and samarium (Sm) are also used in magnets. Neodymium magnets are some of the strongest on Earth.
Types of Magnets
Generally magnets are of two types They are Namely
- Permanent magnets
- Electro magnets.
1. Permanent Magnets
Permanent magnets are those we are most familiar with, such as the magnets hanging onto our refrigerator doors. They are permanent in the sense that once they are magnetized, they retain a level of magnetism. As we will see, different types of permanent magnets have different characteristics or properties concerning how easily they can be demagnetized, how strong they can be, how their strength varies with temperature, and so on.
An electromagnet is a tightly wound helical coil of wire, usually with an iron core, which acts like a permanent magnet when current is flowing in the wire. The strength and polarity of the magnetic field created by the electromagnet are adjustable by changing the magnitude of the current flowing through the wire and by changing the direction of the current flow.
Differences between Permanent magnet and Electro magnet
|It produces a magnetic field as long as the current flows through its coils.||It produces a permanent magnetic field.|
|An electromagnet can produce very strong magnetic force.||A permanent magnet produces a comparatively weak force of attraction.|
|The magnetic field strength can be changed.||The magnetic field strength cannot be changed.|
|The polarity of an electromagnet can be reversed by changing the
direction of current in its coil.
|The polarity of an permanent magnet is fixed and cannot be reversed.|
|It can be easily demagnetized by switching off the current.||It cannot be easily demagnetized.|