Chapter 4 Flashcards
What causes magnetism
When electrons are in motion, a magnetic field is created perpendicular to the motion
Flux density is determined by?
Both field and strength and which the lines of flux are located
Unit of measurement for magnetic flux
Weber (Wb)
Unit of measurement for flux density
Tesla (T)
Classifications of magnets by production
- Natural magnet
- Artificial permanent magnet
- Electromagnet
Natural magnet
Created when iron oxide remains in the earths magnetic field for a long time until their magnetic dipoles are in the same direction
Ex lodestone
Artificial permanent magnet
These are manufactured by steel alloy called albino which is composed of aluminum, nickel, cobalt
Electromagnet
A temporary magnet produced by an electrical current
Laws of magnetism
- Repulsion Law
- Inverse square law - the force between 2 magnets are inversely proportional to the square of the distance between them
- Magnetic pole law - all magnets have 2 poles
Magnetic induction
It will temporarily become magnetized when it comes into the line of flux
Permeability
Refers to the ease in which a material can be magnetized
Retentivity
Refers to the ability to the material to stay magnetized
Magnetic classification of materials
- Ferromagnetic
- Paramagnetic
- Diamagnetic
- Non-magnetic materials
Solenoids
Loops that create a coil with current going through it
Electromagnet
Solenoid with a ferrimagnetic core
The strength of a solenoid or electromagnet is determined by
of loops
The strength of the current
The permeability of the magnetic core
Mutual induction
Solenoids placed near each other and a
current is supplied - primary
Current is induced - temporary
Transformers
Are used to change voltage
Step up & step down transformer
Step up - increase voltage decrease amps
Step down - decrease voltage increase amps
