Magnetism Flashcards
(14 cards)
What is a magnet?
-An object with a North and South Pole
-Attract magnetic materials
-Can attract/repel other magnets
What do magnetic field lines show?
-the shape of the field
-the direction of the fields lines
-the strength of the magnetic field
What direction do magnetic field lines travel?
North to South
How do the magnetic field lines show the strength of the field?
Closer lines = stronger
How can magnetism be INDUCED in magnetic materials?
By placing them in a magnetic field
Hard magnet
Magnetic materials that can be PERMANENTLY magnetised
Soft magnet
Magnetic materials that are only TEMPORARILY magnetised
What type of magnetic cores do electromagnets use?
Soft magnets that can be turned on and off
What do electromagnets consist of?
a coil of wire wrapped around a soft core
What is a solenoid?
A current carrying coil
How does force of an electromagnet change with current?
The higher the current the higher the force
What do DC motors consist of?
A coil of wire in between two permanent magnets
What do split ring commutators do in DC motors?
reverses the direction of the current every half turn
Practical to tell the direction of field lines in a bar magnet?
-Place a bar magnet on a piece of paper
-sprinkle iron fillings evenly over the paper
-gently tap the paper to allow the iron fillings to settle
-the fillings will form the magnetic field lines showing the direction to be NORTH TO SOUTH
