Magnets
A magnet is an object that attracts and repels materials that consist of iron (Fe). It has north and south poles and attracts the opposite and repels a like (similar) pole. It could either be natural or man-made.
1.0Understanding Magnets
A magnet is an object that produces a magnetic field and has the ability to attract or repel certain materials, typically ferromagnetic substances like iron, cobalt, and nickel. There are two poles of Magnets: a North Pole and a South Pole.
2.0Characteristics of Magnets
- Magnetic Poles: A magnet has two poles: the North Pole and the South Pole. Like poles repel each other, and unlike poles attract each other.
- Attraction and Repulsion: Magnets attract ferromagnetic materials (iron, cobalt, nickel) and repel other magnets' like poles.
- Magnetic Field: A magnet produces a magnetic field around itself, with lines emerging from the North Pole and curving towards the South Pole.
- Induced Magnetism: Materials under a magnetic field can get magnetised and display properties of magnetism.
- Force of Magnet: The direction in which the magnetic force exists; it is strong at the poles and weak in the centre of the magnet.
3.0Types of Magnets
- Permanent Magnets:
- Maintain magnetism for a long time without the need for an external power source.
- Examples: Bar magnets, horseshoe magnets, and earth magnets (e.g., neodymium magnets).
- Temporary Magnets:
- Become magnetised when exposed to a strong external magnetic field but lose their magnetism once the external field is removed.
- Examples: Soft iron, which is very common in transformers and electromagnets.
- Electromagnets:
- Magnets are produced by an electric current passing through a coil of wire (often coiled around a ferromagnetic core).
- The strength of the magnetic field can be manipulated by adjusting the current or the number of coils.
- Used in motors, MRI machines, and electric bells.
4.0Difference Between Electromagnet and Permanent Magnet
5.0How to Make a Magnet
In making a magnet, a material, usually iron, is exposed to a strong magnetic field, which causes the domains in the material to align. This can be done by
- Rub the material with a permanent magnet in one direction to align the magnetic domains.
- The placement of material in a magnetic field by a magnet or an electric current.
6.0Magnetism
Magnetism is a physical phenomenon arising due to the motion of electric charges, leading to attraction and repulsion forces among bodies. It is a phenomenon present in materials with magnetic properties that generate a magnetic field or can be influenced by an already existing magnetic field. Magnetism is influenced by three types of materials present in an object: Diamagnetic, Paramagnetic, and Ferromagnetic.
- Diamagnetic Materials: Diamagnetic materials demonstrate a weak repulsion to the magnetic field; this weak magnetism is also named “Diamagnetism”. Their atoms will generate tiny induced magnetic fields opposite to the applied magnetic field, which causes the atoms to be repelled very weakly. Example: Copper, Bismuth, and water.
- Paramagnetic Materials: Paramagnetic materials show weak attraction to magnetic fields (a phenomenon known as Paramagnetism) because of the alignment of their magnetic moments, which is temporary and disappears as soon as the external magnetic field is removed. Examples: Aluminium, platinum, and magnesium.
- Ferromagnetic Materials: Ferromagnetic materials are characterised by strong magnetism (also known as Ferromagnetism) because of the alignment of their internal magnetic domains. They tend to align with the field when exposed to a magnetic field and can even retain their magnetism after the external field is removed. Examples: Iron, Cobalt, and nickel.
7.0Related Questions on Magnet
Question 1: Why does a compass needle point north?
Answer: A compass needle is a small magnet, and so it aligns with the Earth's magnetic field, whose magnetic North Pole is near the geographic South Pole; therefore, the compass needle points toward the Earth's magnetic North.