Electricity and Magnetism Flashcards
What is an electrical conductor?
An electrical conductor is a material that allows the flow of electric current.
What is an electrical insulator?
An electrical insulator is a material that does not allow the flow of electric current.
Name some good electrical conductors.
Some good electrical conductors include metals (some are better than others), graphite (a form of carbon), and salt water.
Name some good electrical insulators.
Some good electrical insulators include wood and plastic (most non-metals).
Draw the circuit symbol for a cell.
A cell is represented by a long line and a short line.
Draw the circuit symbol for a battery.
A battery is represented by two or more cells connected together.
Draw the circuit symbol for a bulb.
A bulb is represented by a circle with a cross inside.
Draw the circuit symbol for a switch.
A switch is represented by a break in a line with a small lever.
Draw the circuit symbol for a variable resistor.
A variable resistor is represented by a zigzag line.
Draw the circuit symbol for an ammeter.
An ammeter is represented by a circle with an ‘A’ inside.
What instrument is used to measure current?
An ammeter is used to measure current.
What does an ammeter measure?
An ammeter measures the amount of current flowing through a circuit.
What is the unit of current and what is its symbol?
The unit of current is amperes, symbolized as ‘A’.
What happens when I increase the number of cells in my battery?
The current will increase.
When the charge moves through the cell, what does it gain?
It gains energy.
Energy per unit charge is also known as?
Energy per unit charge is known as potential.
What is the unit of potential?
The unit of potential is the volt, symbolized as ‘V’.
If I connect more bulbs in series, what happens to the resistance and current?
The resistance will increase and the current will decrease.
What is the unit of resistance?
The unit of resistance is the ohm, symbolized as ‘Ω’.
What is current?
Current is the amount of charge passing a point each second.
What is the important rule to remember at a junction in a circuit?
The total current in must equal the total current out.
Which poles of a magnet attract each other?
The opposite poles (North and South) attract each other.
What happens when like poles of magnets come together?
They repel each other.
Give some examples of magnetic materials.
Examples of magnetic materials include iron, steel, cobalt, and nickel.
Give some examples of non-magnetic materials.
Examples of non-magnetic materials include plastic, wood, paper, rubber, and 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?
A magnetic field is the region around a magnet where other magnetic materials experience a force.
How are magnetic fields represented in diagrams?
Magnetic fields are represented by magnetic field lines.
How could you visualize the field around a magnet?
You can visualize the field using iron filings or a compass.
Draw the magnetic field around a bar magnet.
The magnetic field around a bar magnet is represented by lines emanating from the poles.
Draw the magnetic field around the Earth.
Remember - the Earth’s geographic north pole is a magnetic south pole (we still call it magnetic north when referring to where our compass needle points!)
What is the shape of a magnetic field around a wire and how can we tell the direction?
The shape is circular. The right-hand ‘thumbs up’ rule is used: thumb points in the direction of the current, fingers curl in the direction of the field.
What do we call the effect when a current flows in a wire and generates a magnetic field?
This effect is called electromagnetism.
Draw the magnetic field around a coil/solenoid.
The magnetic field around a solenoid is represented by concentric circles.
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?
A relay circuit is used to activate high voltage circuits using low voltage circuits, protecting the user from high currents.
List some uses of electromagnets.
Electromagnets are used in relays, scrapyards to move parts, maglev trains, and electric motors.
