4th - Magnetism And Electromagnetism Flashcards
(37 cards)
Like charges …
Repel
Opposite charges…
Attract
Example of a magnetically soft material
Use?
Iron
- electromagnets
Example of a magnetically hard material
Use?
Steel
- permanent magnets
How does iron become magnetised
The presence of a magnetic field, which forces magnetic domains into alignment
Examples of magnetic metals
Steel
Iron
Nickel
Examples of non magnetic materials
Wood
Aluminium
What happens if a magnetic field is removed
Magnetism is lost
- domains go back to random orientation
What does it mean if a material is magnetically soft
It loses its magnetism easily if removed from a magnetic field
What does it mean if a material is magnetically hard
It’s domains are locked in alignment - doesn’t lose magnetism easily when removed from a magnetic field
How can aligned domains be effectively jumbled
Heating or striking the magnets on a hard surface
What do magnetic material feel when they are in a magnetic field
Magnetic force
Definition of a magnetic field
A region where a magnetic material experiences a force
What does magnetic field line show the direction of
Direction of the magnetic force ( from north to south)
Which ways will the arrows be pointing on a magnetic field line
North to south
How does the magnetic field lines convey the strength of a field
Tightly packed field lines indicate a strong magnetic field
- practical
Investigate the magnetic field pattern for a permanent bar magnet, and between two bar magnets
( using a compass)
- bar magnet in centre of paper
- compass at edge of North Pole
- mark where North Pole of compass is pointing
- move compass so south end lined up w dot that u just plotted
- mark where North Pole of compass is pointing
- continue until you end at South Pole
- repeat for several field lines
- practical
Investigate the magnetic field pattern for a permanent bar magnet, and between two bar magnets
(Using iron filings)
- paper over bar magnet
- iron filings sprinkled over paper ( they become induced magnets )
- tap paper gently with your finger
- iron filings will line up with field lines
How to create a uniform field
- two bar magnets
- north and South Poles facing
- close, but not too close that they move together
What does a uniform field look like
Evenly spaced
Parallel
Uniform, straight
Do magnetic field lines ever intersect
No
What is a neutral point between two repelling magnets
The resultant field is zero
What is Flemings left hand rule
First finger = magnetic Field
seCond finger = Current
Thumb = force
What is a solenoid
A coiled wire
