Electromagnetism Flashcards
magnetic poles
North and South poles attract. Unlike poles repel
permanent magnet
has its own magnetic field
induced magnet
becomes a magnet when put in a magnetic field. Loses it when removed.
Magnetic field, B
REGION AROUND A MAGNET WHICH ATTRACTS MATERIAL.
CAUSED by magnetic field lines
Strongest at poles of a magnet
Known as magnetic flux density, B measured in Tesla T
Magnetic field lines
Closer the lines the stronger the magnetic field
Earths magnetic field
Acts like a giant bar magnet
Magnetic material
Are attracted by magnetic fields;iron steel cobalt and nickel
solenoid
A coil of wire looks like a spring
magnetic field around a wire
if a wire carries a currentit becomes an electromagnet
magnetic field around a solenoid
if a wire is coied and carries a current it becomes an electromagnet
magnetic field inside is strong and uniform
outside looks similar to a bar magnet
increasing strength of electromagnet
add an iron core
increase current
more coils
motor effect
a wire carrying a current at a right angle through a magnetic field feels a force
size of motor effect force
Force=magnetic x current x length flux density
direction of motor force
is given by Flemings Left hand rule
Increasing force of a motor
more current
stronger magnetic field
more coils
electric motor
coil of wire carrying a current inside a magnetic field. Each side moves in different direction causing it to rotate.
Commutator
Stops motor wires twisting
What is Electromagnetic
Electromagnetic effects are used in mtors to make things move, generators to provide electricity and automatic locks on security doors. Magnetism is far more useful to us than just helping pigeons to navigate.
