P3.3 Magnets and fields Flashcards
What do you call the number of magnetic field lines passing through a particular area?
Magnetic flux density
True or False:
Magnetic fields lines move, north to south
True
What does the density of the field line show?
The strength of the magnetic field
What is an induced magnet?
A material that becomes a magnet when it is placed in a magnetic field
What is a permanent magnet?
A material that produces its own magnetic field and remains magnetized without needing an external magnetic field
If current is going upwards, which ways are the magnetic fields lines going? How can you remember this?
Right hand thumbs up. If thumb is pointing up, current is going up and the fingers which wrap around tell you the magnetic field lines
What does the strength of the magnetic field around the wire depend on?
Magnitude of the current: bigger current = stronger field
Distance from wire: nearer the wire = stronger field
What is the strength of a magnetic field measured in?
Teslas
The strength of the magnetic field depends on the number of coils (more coils =_____ field
stronger field
Is the magnetic field inside the solenoid strong or weak?
Strong
If you put a magnetic material inside a solenoid, what does it do to the field?
Makes it stronger
Is the field produced when a solenoid is wrapped around a magnetic material a induced or permanent magnet?
Induced
What are the three Flemmings left hand rule components?
Thumb = movement
First Finger = field
Second finger = current, P to N
How can you get a coil of wire to spin?
Put a piece of wire into a loop and place the loop into a magnetic field. Then connect the wire to a battery.
How does an electric motor work?
Current needs to be moving in on the right and out out of left. Use a spilt ring commutator
How can you change the speed of the motor?
Change the magnitude of the current
Strength of the magnetic field
Number of coils of wire
Length of coil
