UNIT 5 Flashcards
Magnetism
magnets can occur … or can be …
naturally , man-made
what is a magnet
an object that can attract other objects containing iron, cobalt, or nickel
give exemple of naturally occuring magnetic material mineral
Magnetite composed of iron and oxygen
what makes a magnet magnetic
DOMAINS (aka the arrow sections)
when is a substance magnetized
when the domains allign (aka the arrows point in the same direction)
what creates tiny magnetic fields
the spin of the electrons (since each domain is made up of many atoms)
what is a ferromagnetic substance
a substance with the ability to acquire magnetic properties
all magnets have a … and a… even if you
NORTH , SOUTH (even if you break it in two)
oposite poles …
same poles…
oposite poles attract
same poles repel
describe magnetic field?
the space around the magnet hwere the magnetic force of a magnet can be felt
what does NO SIN stand for
North Out South IN (so the arrows point out for north and in for south)
always … to …
north to south
what determines the strength of the magnetic field
the closer the lines are together, the stronger the field
explain compasses
- it points towards the Earth’s geographic North
- but it actually points towards the Earth’s magnetic South
describe how to use the right hand rule
- conventional current goes + to - so point your thumb towars - (aka away from positive)
- then your fingers wrap in the direction of the magnetic field
current intensity can
(the rate of electron flow) can generate a magnetic field
what is a solenoid?
a cylindrical coil of live wire
a solenoi is … so it acts like a…
coiled, bar magnet
describe how the OTHER right hand rule works for solenoids?
- first wiht your right hand wrap your finger in the direction of the conventional current (aka the way the wires coil)
- then your thumb is pointing to the direction of the NORTH pole of the magnet
3
how can the power of an electromagnet be increased
- using a ferromangetic core with a lower magnetic remenance
- increasing the current intensity
- adding more loops
what does having low remenance mean
its domains can easily be alligned (so they lose their alignment very easily)
3
explain the use of solenoids in technological applications
- the magnetic field can be switched on or off
- the direction of the magnetic field can be easily switched
- the intensity of the magnetic field can be modified (raise/lower the current intensity or add/emove loops)
solenoid can be transformed into what and how
electromagnets (by inserting a ferromagnetic core inside)
exemples of what solenoids are in
vending machines, printer, syringe pumps, door bell and locks, washing machines
earphones, electric motor, magnetic crane
