Electricity And Magnetism Flashcards
What is A material which easily allows an electric current is
an electrical conductor
What is A material which does not allow an electric current is
an electrical insulator
Name some good electrical conductors
Any metal (some are better than others!), graphite (a form of carbon), salt water
Name some good electrical insulators
Wood, plastic (most non-metals in fact)
What instrument is used to measure current?
Ammeter
What does an ammeter measure?
Current
What is the unit of current and what is its symbol?
Amperes A
If I increase the number of cells in my battery the current will…?
Increase
When the charge moves through the cell it gains…?
Energy
Energy per unit charge is also known as….
Potential
What is the unit of potential?
Volt V
If I connect more bulbs in series with each other the resistance will…and the current will….
resistance will increase and the current will decrease
What is the unit of resistance
ohm, Ω
What is a current
The amount of charge passing a point each second
At a junction in a circuit what is the important rule to remember?
Total current in = total current out
Which poles of a magnet attract each other?
The opposite poles (North and South)
What happens when like poles of magnets come together
They repel
Give some examples of magnetic materials
Iron steel cobalt nickel
Give some examples of non-magnetic materials
Plastic wood paper rubber glass
Why does the earth have a magnetic field
The core of the earth is a rotating ball of Iron
What is a magnetic field
The region around a magnet where other magnetic materials experience a force
How are magnetic fields represented in diagrams?
Magnetic field lines
How could you visualise the field around a magnet?
Iron fillings or using a compass
What is the shape of a magnetic field around a wire and how can we tell the direction of the field lines?
Circular. Right hand “thumbs up” rule. Thumb points in the direction of the current, the fingers curl in the direction of the field
When a current flows in a wire a magnetic field is generated. What do we call this effect?
Electromagnetism
Name 3 ways to increase the strength of the magnetic field around a solenoid
”* Increase the current * Increase the number of turns on the coil * Add an iron core”
What is one of the major advantages of an electromagnet compared to a permanent magnet
Electromagnets can be switched on and off
What is a relay circuit used for
To activate high voltage circuits using low voltage circuits (this protects the user from high currents)
List some uses of electromagnets
In relays (e.g. to switch of floodlights or x-ray machines in hospitals), in scrapyards to move parts, maglev trains, in electric motors, in rollercoaster braking
