Electricity Flashcards
What is the main problem with generating electricity?
Generating electrify creates pollution
What are the advantages of using mains electricity?
Covenient
Safe
Using it is pollution free
How do batteries work?
Convert chemical energy -> electrical energy when in circuit
Give 3 alternatives to electricity
Gas
Biomass
Solar energy
What is an LED? How does if work?
Light Emitting Diode
Electrons in LED absorbed energy from supplied voltage, release energy as light
Why is the light from an LED always 1 colour?
Same energy absorbed and released by all electrons
What is power and its’ unit?
Rate of energy transfer (W)
How does the size of a current affect the energy in the current?
Larger current = more energy
How does the power of equipment affect the cables?
More powerful equipment = thicker cables
How are cables designed to make them as efficient as possible?
Designed to heat up as little as possible
How are heating/lighting filament wires designed?
Designed to heat up loads - less efficient, more heat/light
How do you calculate the cost of electricity?
Cost = kilowatt hours × cost per hour
How do power stations generate electricity?
Fuels burnt, or nuclear fission
Heat created heats water -> steam -> drives turbine -> spins generators -> generates electricity
Explain the energy changes in each part of power stations
Boiler: Chemical -> heat
Turbine: Heat -> kinetic
Generator: Kinetic -> electrical
Transformer: Electrical transfer
Energy wasted at each step
How can power stations be made more efficient?
Using waste energy directly for heating -> 70-80% efficient
