Electricity and Magnetism Flashcards
What is electricity and its use
Electricity is the movement of electric charge. It is useful for energy transfers involving electrical energy.
Describe the difference between static electricity and current electricity
Static electricity is caused by the accumulation (charge at rest) of charge on the surface of the body.
Current electricity is caused by the movement of charge or electrons
Explain what a conductor is
Conducts electricity sinceit offers little or no resistance to the flow of electrons
Explain what an insulator is
An insulator does not conduct electricity. An insulators a material thatresists the flow of electrons
Explain static electricity as a buildup of charge
Static buildup is when electric charges are exchanged between two surfaces that are in contact.
In this process, one object takes on a positive charge and the other a negative charge. It is because of this that static electricity builds up on the surface of objects.
Describe some uses of static electricity
Photocopiers and inkjet printers use static electricity to ensure that toner sticks to the paper. Electrostatic paint spraying uses static electricity to get an even paint
Explain why static electricity can be dangerous
Aeroplanes and rescue helicopters.
State the conditions required for electrons to move along a conductor
For electrons to flow continuously through a conductor, there must bea complete, unbroken path
for them to move both into and out of that conductor.
Use standard circuit symbols to describe a simple electric circuit
Explain the difference between a series circuit and a parallel circuit
Series:
- components are all connected one after another
- there is only one path electrons can take
- Voltage of the battery is shared across all of the components and current is the same
Parallel:
- components are connected side to side
- several paths are available to the electrons.
- Voltage of the battery is the same and current is shared across all of the components
Explain electric current
An electric current is a flow of charge.
what is currents measured in
Amps from an ammeter (A).
What is the law of conservation of charge
Law of conservation of charge says thatthe net charge of an isolated system will always remain constant.
What is energy carried by
Electrons
What does voltage measure
Voltage measures the energy carried by electrons.
What does voltmeters measure
Voltage and compares energy on each side of the component and shows the energy difference between 2 points.
Understand the definition of power
Time and rate of doing work or delivering energy.
Calculate power using voltage and other data
Power in Watts is calculated bymultiplying voltage in Volts times current in Amps.
- P = VA
Explain what a “kilowatt-hour” is
kWh stands for kilowatt hour (kWh) – it’s the way we measure energy in the home.
total cost: total kWh x price of 1 kWh
Calculate the cost of electricity using power and time data
Multiply the power rating (watts) by the amount of time (hrs) and divide by 1000.
Describe methods of controlling electric currents
Switch: A device that interrupts the electron flow in a circuit.
Fuse: If too much current flows, the fuse wire rises to a higher temperature and melts, which opens the circuit but destroys the fuse.
Circuit breakers: A type of electrical switch which heats up and cuts the power when current levels are too high.
List the safety precautions for an electrical accident
- Always Cut the Power
- Investigate Flickering Lights
- Don’t Use Extension Cords Long-Term
Understand magnetic attraction and repulsion
Like sides (south and south, north and north) will repulse.
Unlike sides (south and north) will attract.
Map magnetic fields
State which types of materials are magnetic
Ferromagnetic substances; nickel, iron, and cobalt. Steel is an alloy containing iron, therefore it is also ferromagnetic.
Understand what happens inside a magnet
Magnetic materials have regions that are magnetic domains. These are not lined up in a direction and so tend to cancel each other out. However, when a magnet is made these domains line up making it magnetic.
Test magnet strength
Investigate the weight of what the magnet can lift up.
State how to make a magnet
- Cool iron in a magnetic field
- Move a magnet up and down on a piece of iron
- Hammer a nail in a magnetic
- Put a piece of iron in an electric field
Understand that electricity and magnetism are linked
A changing electric field creates a magnetic field, and a changing magnetic field creates an electric field.
Make and test a simple electromagnet
Investigate and state the factors that affect the strength of a simple coil electromagnet
- Current: increasing the current in the wire
- Coils: the more coils the stronger the magnet
- Core: adding a core of iron such as a single steel bar or bundle of wires.
State some applications of electromagnets
What is an electromagnet/solenoid
A wire carrying a current that has a magnetic field around it.
What is a motor
Converts electrical energy into kinetic energy.
What is a generator
Something that generates electricity
Why is an electromagnet better
An electromagnet can always be turned on and off.
