Electricity and Magnetism Flashcards
Electrical energy
-Type of kinetic energy
-Produced by charged particles
-Highly convenient
What is electricity?
Is the movement of electrons from negative to positive (cause electrons=negative charge)
Static electricity
-Imbalance of electrical charges that build up on the surface of an object
-Can cause lighting electric shocks
-opposite charges attract
current electricity
-Flow of electrons through an electrical conductor
What is a conductor?
Material where some electrons are free to move and can flow in an electric current.
What is an insulator?
Material where electrons are tightly held and cannot move, so electric current cannot flow.
How does static energy build up?
When two insulating materials rub together, such as a comb through hair. Friction between these materials can pass electrons from one material to the other.
-one material ends up having more electrons, it now has an overall negative charge.
- The other ends up having less electrons, therefore ending up with a positive charge.
Series circuit
Components are connected end to end in a loop. If one component breaks, the whole circuit will go out and none of the bulbs will light as the circuit is no longer complete.
EG Christmas lights
Parallel circuit
The components are connected side by side. This gives the current several different pathways for it to flow around. If one bulb breaks, the other bulbs will remain, as the circuit is still complete.
What is current?
Measure of flow of electric flow of electrical charge in a circuit.
Measured in amps using an ammeter.
Current in series?
the same in all parts of a series circuit.
Current in a parallel?
Shared between branches
What is voltage?
Measure of the difference in electrical potential energy between 2 points in a circuit.
Voltage in series?
Supplied voltage shared between components.
Voltage in parallel?
Voltage across the components is the same.
What is power?
Power is how much energy is transferred from one form to another in a second.
Measure in watts (W)
Calculations for power?
Energy/time or current/voltage
Cost calculations
kwh
e.g 2.5 kw of power for 5 hours at 25 cents…
(2.4 x 5)x 0.25
Resistance
A measure of how easy it is for current to flow through a circuit.
High resistance= low current flow
What does a magnet do?
-Object that exerts force on another magnetic material
-Does not have to be contact between the objects
-Space in which the force is exerted is called the magnetic field
-Magnetic materials ; iron(steel), cobalt and nickel
Opposite poles…
attracts
Like poles …
repel
Magnetic field attributes…
The stronger the magnetic field the closer the magnetic field lines.
Law of magnetism
-All magnets have two poles
-Opposite poles attract, same poles repel
-magnetic fields are stronger at the two poles, where the fields lines are closer together
what are domains?
a region inside a material where groups of magnetic moments naturally align in the same direction.
When domains point different directions, the magnet is demagnetised
How do you destroy a magnet?
Sticking a magnet with a hammer or heating it. This causes the domains to face all different directions
Magentic strength unit=…
T for tesla
Making magnets.
By contact or strocking a magnet material against a permanent magnet.
What is an electromagnet?
Consists of a core material such as iron surrounded by wire coil, through which a electric current is passed.The current comes from a battery on power pack, when the electric current flows it becomes electric.
