P1.5 Flashcards
What is electricity
A flow of charged particles
What is currant
Rate of the charge flowing
What is voltage
An electrical pressure that measures the amount of energy transferred by the charges
What are solar cells
Objects that convert solar energy directly into electricity
Why is natural gas cleaner than coal
Cmon twins less nitrogen so less nitrogen oxides released, doesn’t contain sulphur so no sulphur dioxide. Also emit less carbon dioxide than coal
What are negatives of nuclear energy
When problems occur, they can be very bad, meltdowns
After their life, they need to be decommissioned, making sure no nuclear material gets into the environment, this is very expensive
Expensive to build
Waste materials need to be safely disposed of and contained which is eqxpensive
Benefits of nuclear energy
No dangerous gases or ash so much cleaner
Cheap to run
Lots of energy for amount of fuel run
What is electromagnetic induction
The process of when a metal wire is moved in a magnetic field, creating a currant in the wire. This is an induced currant
How can an induced currant be increased
More coils of wire
Using an iron core
Using stronger magnets
Moving the wire faster
How can currant direction be changed
Direction of wire movement,
Changing the direction of the magnetic field
What is dc currant
Direct currant, the currant always moves in the same direction
How does a generator work
There is a coil of wire with an iron core that rotates between two magnets. As it rotates a currant is induced, as each side goes under the magnetic field and then over it, it’s an alternating currant. Th currant is transferred from the wire onto slip rings so the energy can be transferred without tangling the wires. The currant in then in a stationary circuit.
Why is currant transferred through the national grid at such a high voltage
It means the wires in the grid don’t heat up so much so less energy is lost through heat into the environment.
What is the different voltage changes in the national grid
Power station 25kV Wires 400kV Factories 11kV Wires in town 33kV Homes 230V
What is a transformer
Something that changes the voltage of alternating currant, increasing it or decreasing it
What does a step up transformer do
Increases voltage and decreases currant
What does a step down transformer do
Lowers voltage and increases currant
What is the structure of a transformer and how does it work
Iron core with two sets of wire. Primary and secondary coil. Currant enters primary and is obtained at the secondary at a different voltage
What is the formula for voltage produced by a transformer
Primary voltage/secondary voltage = num coils primary/ num coils secondary
What is the unit for energy
Joules J
What is power and unit
The amount of energy an appliance used every second measured in watts. 1 watt = 1J per second
Formula for power
Energy used J / Time S
Currant A * voltage V
Cost of electricity
Cost p = power W * Time H * cost of 1kWh
What does increasing voltage do
Decreases the currant, so less energy lost through heat so in nat grid, its more efficiant
Structure of transformer
Iron core in coils of wire. Primary coil and secondary coil. In step up, primary coil has less coils than secondary coil. The coils of wires do t touch
Potential difference transformer equation
Voltage on primary/voltage on secondary
Turns of coil on primary/ turns of coil on secondary
Vp/Vs == Np/Ns
How can an induced currant be increased
Use a coils of wire instead of single piece. Or use more coils
Uses an iron core in the wire
Use stronger magnets for stronger magnetic field
Move wire faster
What causes direction of movement in currant
The direction of the movement of the wire
The direction of the magnetic field
