Magnetism Flashcards
What are the only pure magnetic metals?
Iron, Cobalt and Nickle
Steel is also magnetic though because it is an alloy and has iron in it.
What are temporary magnets?
Are not always magnetic.
Eg Electromagnets can be turned on and off OR induced magnets – only magnetic in another magnetic field.
Made of magnetically soft materials.
Uses – scrapyard cranes, metal detectors
What are permanent magnets?
Always magnetic (but can becomes weaker over time)
Made of magnetically hard materials
Uses – compass, fridge magnet.
What is a solenoid?
A coil of wire with current flowing through it, this creates a magnetic field.
How can you increase the magnetic field in a solenoid
Add more coils of wire
Increase the current
What is an electromagnet?
A solenoid with an iron core in the middle of it
How do you make an electromagnet stronger?
Add more coils
Increase the current
What is electromagnetic induction?
Making electricity using magnets.
How is electricity generated using electromagnetic induction?
If you either move the magnet on and out of the coil OR spin the coil inside of the magnets it cerates electricity (induces a voltage).
How do you increase the electricity generated in electromagnetic induction?
To make more, move the magnet or wire faster, stronger magnets, more coils.
What does a step up transformer do?
Increase the voltage
This then decreases the current.
Less current means less electrons to collide with the ions in the over head wires.
Less heat is made therefore making the transmission of electricity more efficient.
What does a step down transformer do?
Decrease the voltage
This increases the current.
It makes it safe to use
What is the right hand rule?
A straight piece of wire will have a magnetic field if there is current flowing through it. To work out the direction of this field we use the right hand rule and our thumb has to point in the direction the current is going.
