Permanent and induced magnetism, magnetic forces and fields Flashcards
where is the magentic force the strongest on a magnet?
on the poles of the magnet
what is a permanent magnet?
a magnet which produce their own magentic feild and are always magnetic
what is an inuced magnet?
an induced magnet is a material which becomes a magnet when placed in a magnetic field
what are some magnetic materials?
- iron
- steel (strongest magnetic material)
- nickel
- colbalt
what is the direction of the magnetic field?
north to south pole
what is a magentic field?
the region around a magnet where a force acts on another magnet or on a magnetic field
what does the strength of the magnetic field depend on?
the farther away the magnetic feild if from the magnet the weaker it is
how can we plot the magnetic field patterns using a compass?
- place the compass near the north pole of the bar magnet
- then draw a cross at the noth pole of the compass
- we move the compass so the south pole of the compass is on the cross
- Again we draw another cross at the north pole of the compss
- continue doing this until we have completed drawing the magnetic feild line
- connect all the dots and use an arrow to show the direction of the magnetic field
- repeat this starting at different parts around the north pole of the magent
how is the behaviour of a magnetic compass related to evidence that the core of the Earth must be magnetic?
- a magnetic compass contains a small bar
magnet - if we hold the compass the needle always face the north- south direction
- shows the earth has its own magentic field
- and the eartch magentic field is due to its core
what is a conventional current?
current flows from positive to negative
how can we prove their is a magentic field around a wire that has been induced by current?
- when current is turned off the compass needle lines up with the earths magnetic field
- when the current is on the compass needle deflects
in a circuit where their is a wire what does the strength of the magentic field depend on?
- size of the current
- strength of magnetic field is also strongest closest to the wire
what happens when current flows through a wire?
a magnetic field is
produced around the wire.
how can we work out the direction of magnetic field produced by a wire?
wrap your RIGHT hand around the wire and plave your thumb in the direction that the currrent is flowing.
this is felmming rights hand rule
how else can we increase the magnetic field apart from current?
coil the wire which is call a solenoid
what are the three ways we can increase the strength of a magentic feild prodcued by a solenoid?
- increase size of current
- increase number of turns by the coil
- core- placing a peice of iron insdie the solenoid
what is a solenoid?
a coild of insulated wire
what is a solenoid containing a iron core called?
an electromagnet
