# GCSE: Physics

I GOT ALL THIS INFORMATION OUT OF MY CLASSWORK BOOK AND NOTES. ITS NOT COMPLETE BUT WHEN I GET NOTES ON ELECTROMAGNETIC SPECTRUM I WILL UPDATE IT :D

chelly. xxxx

• GCSE: Physics
• Generating electricity
• Sources of energy
• NON-RENEWABLE:coal, oil and gas
• RENEWABLE:hydro-electric, nuclear, wind
• Efficiency: fossil fuel power station approx. 40% efficient. Wind turbine is approx. 50% efficient
• Transmission of electricity
• Power stations generate around 30,000v
• it is then increased using a step up transformer to around 275,000v.
• carried around the national grid to supply  demands, then reduced by step down transformer to around 230v (in britain)
• National gird! network of wires and cab els above and below ground connects to power stations ad homes
• power= voltage X current (w= v X a)
• E.G, find the power of an iron that has a current of 4A and voltage 230v . You should get 920v
• Energy supply and the home
• energy (j)= power (w) X time (s)
• cost= cost per unit x no of units
• Energy Transfer
• conduction:mainly happens in solids because the particules are tightly packed. Particles get heated up and start to vibrate.
• good conductors: metal.
• convection: happens in liquids and gases. it needs the particles to move.
• Radiation: does not need particles for the heat to travel through.
• Black matt surfaces absorb & admit heat. Shiny white surfaces reflect and are poor absorbers and poor emitters,
• Waves and the electromagnetic spectrum
• waves: characteristics of waves. we have two types of waves: longitudinal and transversal
• longitudinal: need something to travel through. it compresses the particles. Sound is a an example.
• Transversal: dont need anything to travel through. light is an example.
• frequency measured in hz. amplitude. wavelengthmeasured in metres. wavespeed=frequencyx wavelength
• EDEXCEL