Magnetism and Electromagnetism Flashcards
what do all magnets contain?
what do all magnets produce and what is it?
-They contain north pole and south pole
-They produce a magnetic field which is a region where other magnets or magnetic materials experience a non-contact force
what are the 4 magnetic materials?
1-Iron
2-Cobalt
3-Nickel
4-Steel
where is the magnetic field most stronger at and what does it mean?
what is the force between a magnet and a magnetic material?
-The magnetic field is strongest at the poles of a magnetic this means that the magnetic forces are also strongest at the poles
-The force between them is they are always attractive
what happens if two poles are put near each other?
what happens to two like poles?
what happens to two unlike poles?
-They will exert a force on each other
-Two like poles will repel each other
-Two unlike poles will attract each other
-You can show a magnetic field by drawing magnetic field lines
-The lines always go from north to south and they show which way a force would act on a north pole if it was put at that point in the field
-The closer the lines are the stronger the magnetic field the further away from a magnet the weaker the field is
what does a compass contain?
-Inside a compass is a tiny bar magnet.The north pole of this magnet is attracted to the south pole of any other magnet it is near.
-So the compass points in the direction of the magnetic field it is in
-You can move a compass around a magnet and trace it’s position on some paper to build up a picture of what the magnetic field looks like
-When they’re not near a magnet compasses always point north.This is because the earth generates it’s own magnetic field which shows the core of the earth must be magnetic
what are the two types of magnets?
what is the force between them?
what happens if you take away the magnetic field from induced magnets?
-Two types of magnet is:
Permanent magnets produce their own magnetic field
-Induced magnets are magnetic materials that turn into a magnet when they’re put into a magnetic material
-The force between is always attractive
-When you take away the magnetic field induced magnets quickly lose their magnetism and stop producing a magnetic field
what happens when a current flows through a wire?
what is the field made up of?
how can we see this?
-A magnetic field is created around the wire
-It is made up of concentric circles perpendicular to the wire with the wire in the centre
-you can see this by placing a compass near a wire that is carrying a current as you move the compass it will trace the direction of the magnetic field
what happens when you change the direction of the current?
what do we use to work it out?
what is the right hand thumb rule?
x
-It also changes the direction of the magnetic field.Use the right hand thumb rule
Thumb rule:
Thumb-direction the current up,curl your fingers
Fingers-direction of the field
What is steps of increasing the magnetic field that wire produces ?(3)
1)By wrapping the wire in a coil called solenoid
2)This happens because the field lines around each loop line up with each other
3)This results in lots of field lines pointing in the same direction that are very close together,closer together the field lines are the stronger the field is
what is the magnetic field inside a solenoid like?
what is the magnetic field outside the solenoid?
what does this all mean?
-It is strong and uniform
-Outside is just like one round a bar magnet
-This means that the ends of a solenoid act like the north pole/south pole.You can work it out by using the right hand thumb rule
how do we increase the field strength of a solenoid and what does it become?
what happens if we stop the current?
what is electromagnet?
-By putting a block iron in the centre of the coil.The iron becomes an induced magnet whenever current is flowing
-If we stop the current magnetic field disappears
-Electromagnet is a magnet whose magnetic field can be turned on and off with an electric current
what does the force acting on a conductor in a magnetic field depend on?(3)
how do we work out the size of the force?
-Magnetic flux density (how many field lines there are in a region.This shows the strength of the magnetic field
-The size of the current through the conductor
-The length of conductor that’s in the magnetic field
Equation:
