Electromagnetic Induction Flashcards
What is electromagnetic induction?
The creation of potential difference across a conductor which is experiencing a change in magnetic field
(If the conductor is part of a circuit, a current will flow)
Moving a magnetic in a coil of wire…
Induces a voltage
How can you perform electromagnetic induction?
You can do this by moving a magnet in a coil of wire r moving an electrical conductor in a magnetic field. Shifting the magnet side t side creates a little ‘blip’ of current
How do you reverse the potential difference/current?
Move the magnetic in the opposite direction
The polarity of magnet is reversed
How do you produce an AC current?
If you keep the magnet (or coil) moving backwards and forwards, you produce a p.d that keeps swapping direction
A magnet turning end to end in a coil also creates…
a current
How can you create p.d using a magnet?
You can do it by turning a magnet end to end in a coil, which lasts as long as you spin the magnet. - This iis how generators work
How do turning magnets work to create a current?
As you turn the magnetic field through the coil changes - this change in the magnetic field induces a p.d, which can make a current flow in the wire
When and why does the p.d in a magnet turning thing reverse? What does this cause?
When you’ve turned the magnet through half a turn, the direction of the magnetic field through the coil revers. Therefore the p.d reverses, so the current flows in the opposite direction around the coil of wire
How do you get an AC current from a magnet turning thing?
If you keep turning the magnet in the same direction - always clockwise say - then the p.d will keep on reversing every half turn and you’ll get an AC current
What is genetic induction used for?
To generate a current in appliances
What are dynamos used for?
On bikes to power the lights
How are dynamos used on bikes?
The cog wheel at the top is positioned so that it touches one of wheels. As the wheel moves round, it turns the cog which is attracted to the magnet. This creates a AC current to power the lights
