PHYSICS

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ELECTROMAGNETIC SPECTRUM

Radio waves = tv signal

microwave = cooking, mobile

infrared = optical fibre communication and tv remote 

visible = sight

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LIGHT WAVE

normal line = is an imaginary line at 90 degrees to the surface of the light if being shone at

reflection = the angle of incidence equals the angle of reflection

refraction = light changes speed when it changes the material it is travelling in. When ut goes from air to galss, it goes towards normal. When it goes from glass to air, it goes away from normal

Diffraction = effects gets less obvious as the gap gets longer

virtual image = is the image that you see in a mirror

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THE BIG BANG THEORY

blue      green     yellow      orange    red

galaxies are yellow or orange because they're moving away quickly

moving away = redshift

moving towards = blueshift 

Doppler effect = wavelength 

CMBR = type of microwave, which was at the begginning of the Big Bang Theory

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INFRARED

emitting infrared = 

  • giving out infrared radiation
  • some of the infrared will be absorbed by object
  • best emitters are dark matt surfaces
  • worst emitters are shiney, light surfaces

Reflecting infrared =

  • absorbing infrared radiation
  • some of the infrared will be reflected by the object
  • good reflectors are shiney and light in colour
  • bad reflectors are dark coloured and matt

In non-metals such as plastic, all the electron are held within atoms or molecules. They cant transfer energy


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KINETIC THEORY

when a liquid evaporates, the energy to break the bonds between the liquid particles from the liquid cools down

In a liquid (or a gas) where the particles are moving around, they move at different speeds

when a liquid evaporates, only some of the particles have enough energy to escape the liquid

Because the high energy particles escape, the average energy of those left behind goes down-so the liquid cools

Evaporation absorbs energy from the surrondings which cools down

When a gas condenses, energy released by making new bonds between the liquid particles goes into the liquid, which heats up

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PAYBACK TIME

how long it takes you to save money you spent on energy

There are different ways on how to make your house insulated and still save money. For example, you can have double-glazed windows,to create a vaccum inbetween the gaps. The vaccum would keep the hot air in the house, and prevent any cold air getting in.

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CONVECTION CURRENT AND HEAT SINKS

HEAT SINK = a heat sink is designed to absorb a lot of heat energy from an object, stopping the object becoming too hot. The thermal energy is then transferred to the surronding air. For example, a computer. 

CONVECTION CURRENT = is when the energy from the heat rises up and drops back down. When the energy rises, there is a lower density causing the energy from the heat to drop. 

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POWER STATIONS

  • the coal is heated up and the steam produced is carried along a pipe to a Turbine
  • The Turbine spins around and the steam goes down two pipes. These two pipes lead onto a condenser or a genorater
  • The genorater has a magnet,which makes it spin around. The generator makes the hot steam travel to a transformer
  • The transformer generates the steam into electricity that travels along by wires across the county
  • The other pipe from the Turbine leads into a condenser, which cools down the hot steam from the coal. The now cool steam is carried down to a cooling tower. Convection current occurs in the cooling station and the cool water rises.
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TRANSPORT AND DISTRIBUTION OF ELECTRICITY

  • the national grid = the UK has a national network of power distribution
  • This connects power stations, renewable sources, and also some private sources of electricity 
  • The electricity can then travel to where it is needed via power cables
  • Sometimes it isnt worth connecting a small source of electricity to the National Grid as it costs more than you could make back.

MOVING ELECTRICITY

  • electricity moved through transmission lines
  • when electrons move through the lines, they create heat
  • this is wasted energy 
  • to reduce this as much as possible the voltage is increased and the current is decreased 
  • this is done using a step-up tranformer
  • when the electricity is distributed as its destination it is stepped down usin a step down tranformer 
  • this reduces the voltage and increases the current
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