Chapter - 16 ( Magnetism) Flashcards
What are the ends of a magnet called?
Poles
What are the end poles called?
- South Pole
- North Pole
When do magnets experience attraction?
Unlike poles
When do magnets experience repulsion?
Like poles
What are properties that magnetic materials have?
- Experience a force when placed in magnetic field
- are attracted to magnet when unmagnetised
- can be magnetised to form
Do non magnetic materials experience a force when placed in magnetic material?
No
What are permanent magnets made out of?
Steel (Not always)
Why is steel called permanent magnet?
Tend to stay magnetised
What are the uses of permanent magnets?
- Compasses
- School lab experiments
- Toys
- Fridge magnets
What is the use of electromagnets?
- Use electricity to create a magnet from a current - carrying wire
what are the advantages of electromagnets?
- They can be magnetised and demagnetised at the flick of a switch
- they can be switched on and off
What are the uses of electromagnets?
- MRI scans
- Speakers and earphones
- Recycling
- Mag lev trains
What are the elements that are magnetic?
- Iron
- Cobalt
- nickel
Why is stell also a magnet?
It is an alloy that contains iron
What should we observe when a magnet Is brought closest to a known magnet.
- If it is repelled by known magnet then material is a magnet
- if it can only be attracted and not repelled, then it is not a magnet
What’s re the 2 types of magnets?
- Permanent magnets
- Induced magnets
Wha are the properties of permanent magnets?
- Made of steel
- Produce its own magnetic field
- does not lose magnetism
What’s re the properties of induced magnets?
- temporarily magnet
- induced magnetism
- one end becomes north and the other South
-
What happens when magnetism is induced on a material?
- one end of material becomes north pole
- other end will become South pole
Why are magnetic materials attracted to permanent magnets?
End of a material closest to the magnetic will have the opposite poles to magnet pole closest to the material
What happens when magnetic material is moved away from their permanent magnet?
Loses all it’s magnetic properties
Define magnetic field.
The region around a magnet where a force acts on another magnet or on a magnetic material (such as iron, steel, cobalt and nickel)
What are all magnets surrounded by?
Magnetic field
When is a uniform field created?
When two opp poles are held together and magnetic fields always move from north to south
what does a uniform magnetic field always have?
Same strength and direction at all points
What do the magnetic field lines represent?
- Strength
- Direction
Of magnetic field
What shows the direction of the magnetic field?
arrows
What are 2 important rules to remember when drawing magnetic field lines?
- always go from north to south
- must never touch or cross each other
Where is the magnetic field in a bar magnet the strongest?
At the poles
When does the magnetic field strength in a bar magnet become weaker and why?
- weaker as the distance from the magnet increases
- lines are further apart
How is the strength of magnetic field shown?
- Spacing of lines
Close: String magnetic field
Far: weak magnetic field
