Studied by 4 peopleWhat are the two ends of a permanent magnet called?
North and South poles.
Forces
A push or a pull. repulsion/attraction
Like poles of a magnet (N-N/S-S)
repel each other
Unlike poles of a magnet (S-N/N-S)
Attract each other
repel
to push away
attract
to pull toward
Magnetism
The force of attraction or repulsion of magnetic materials
Electromagnetism
the interaction of electric currents or fields and magnetic fields.
bar magnet
a magnet in the form of a bar with magnetic poles at each end
horseshoe magnet
a type of magnet that has a bend in the middle
magnetic field lines
show the direction of a magnetic field at different points.
What happens if a magnet it cut in half?
It becomes two different magnets
What does the compass indicate in field lines
The lines that run from north to south
Why do magnetic field lines never cross?
Magnetic field lines never cross because they represent the direction of the magnetic force at any point in space.
What happens if magnetic field lines did cross?
the magnetic force would be pointing in two different directions at the same point.
magnetic materials
iron, cobalt, nickel, neodymium
What must me remember when drawing field lines?
Arrows.
Non-magnetic materials
Aluminium, gold, silver, copper
What is a magnet?
A material that exerts a force onto another magnetic material
exerts
puts energy or power into doing something
magnetically hard
Can stay magnetic indefinitely like a bar or horseshoe magnet, producing a permanent magnet
Magnetically soft
Soft materials such as pure iron, can be temporarily magnetised.
What happens if a soft magnetic material is brought in contact with a hard magnetic material?
The magnet field will be induced.
compasses
A compass is a device that tells you which way is north. It has a needle that is magnetized and can move freely.
Where does the needle of a compass point towards
to the Earth's magnetic North Pole
Induction
To create another magnetic field by bringing an opposite pole
permanent magnet
A magnet that will keep its magnetic field indefinitely
temporary magnet
An object that has an induced magnetic field for a short while.
soft magnetic materials
Materials that are easy to magnetize and demagnetize.
hard magnetic materials
A material that is difficult to induce keeping its field indefinitely.
What happens when a current flows through a conductor?
It generates a magnetic field
Unit for current
Amps, A
current
The rate of flow of an electric charge
How could we increase the an electromagnetic force?
Increasing the current ( electricity), increasing the wire length,
What happens when you move a current away from the source of magnetism?
The magnetic strength decreases
What does a loop in flow of current do?
It increases the strength of the field as the fields add together.
Solenoid
a coil of wire with an electric current in it
Why does a solenoid increase the magnetic field strength?
magnetic fields caused by the current in each turn of the coil add together to make a stronger overall magnetic field.
What is the magnetic field of a solenoid similar to?
bar magnet
How could we make the magnetic field of a solenoid stronger ?
By wrapping the solenoid in an iron core making an electromagnet
How is are electromagnets made?
From a solenoid wrapped around iron core.
Advantages of an electromagnet over a permanent magnet
We have more control over electromagnets . You can switch off an electromagnet and vary its current strength.
Uniform field lines
When a magnetic field strength is equal across the whole field.
how to create a uniform magnetic field with two bar magnets?
Placing the opposite poles of two magnets close to each other
Core
soft iron metal which the solenoid is wrapped around
Electromagnet
A non-permanent magnet turned on and off by controlling the current through it.
How can we investigate magnetic fields
Using iron fillings or a plotting compass
Note
Flashcard