Magnetism

Magnetism

created from the electromagnetic force which is one of the fundamental forces found in the universe. Can be an attractive or repulsive force. Its the ability of certain materials to attract certain elements like ion, nickel, and cobalt.

Natural magnet

magnets that exist in nature without any help from humans. Earth is a natural magnet which is why compass is a useful tool for navigation purposes. Lodestone (aka magnetite) is an iron oxide that has remained in the earth’s magnetic field for centuries.

Artificial permanent magnets

man made magnets that are magnetic all the time. Theyre usually made of iron, steel, or alnico. (what)

Alnico

alloy of aluminum, nickel, and cobalt which makes it a strong, light weight magnet

Artificial temporary magnets

they are only magnetized in the presence of an electric current. Usually referred to as electromagnets

Weber’s Theory

used to explain the origin of magnetism and is sometimes known as the domain theory. It states that when a charged particle is in motion, a magnetic force field will be created that is perpendicular to the motion.

Magnetic effect

created by electrons spinning on their axis. Aka electron spin which is basis of MRI. its called spin magnetic movement.

Magnetic domains

atoms having a number of electrons with their magnetic moments in the same direction (esp when the outer shells are involved) will exhibit a magnetic field in a distinct direction.

Magnetic dipoles

group of magnetic domains.

Magnetic field

a zone of electromagnetic force that surrounds a magnet. Magnetic field exists as lines of forces or lines of flux. They can bu sprinkling iron fillings around a magnet. The strength of magnetic field is proportional to the number of force lines per unit area.

Magnetic field relationship

The greater the number of force lines, the greater the strength of the magnetic field (directly proportional)

Characteristics of magnetic lines of force

They flow out of the north pole, travel trough space and then into the south pole of a magnet.

Characteristics of lines of force

They never intersect each other but can expand and contract, They seem to repel each other they travel in the same direction and attract each other when they travel in the opposite direction, The field is distorted by magnetic materials but not be non

Magnetic flux or field strength

this is the number of force lines emitted by the magnet. SI Unit= Weber (Wb). 1 Wb= 10^8 lines of force

Magnetic flux density

the number of force lines per unit area. MKS/SI Unit= Tesla (T) or CGS Unit= Gauss (G)

Laws of magnetic poles

every magnet has two poles, one at each end. One is called north and another is called south because that’s the direction they will point if left alone.

Law of attaction/repulsion

like poles will repel each other. Unlike or opposite poles attract each other.

Cuolomb’s law

the force of attraction or repulsion between the two magnetic poles varies directly with the strength of the poles and inversely with the square of the distance between poles

Susceptibility

the extent to which material becomes magnetized when placed into a magnetic field.

Permeability

the ease with which given material becomes magnetizes by induction

Retentivity

the ability of a magnet to resist demagnetization. Soft iron has a low retentivity while hard steel has a high retentivity

4 classifications of relative permeability

ferromagnetic, paramagnetic, diamagnetic, and non magnetic

Ferromagnetic

strongly magnetic and highly permeable and greatly susceptible to magnetic induction. Like iron, nickel, and cobalt

Paramagnetic

materials that will slightly increase magnetic field strength. Like platinum, aluminum, manganese, oxygen, and gadolinium.

Diamagnetic

these materials will slightly decrease magnetic field strength by repelling magnetic lines of force. Like beryllium, bismuth, copper, carbon and lead

Non magnetic

have no attraction to magnetic field and have no susceptibility. Most of the elements on the periodic table are non magnetic,