Electricity

• what is current?


  the rate of flow of charge
• what is a series circuit?

  current flows through one continuous path, the current is the same at all parts

  voltage is shared
• what is a parallel circuit?

  current splits in a parallel circuit, if there's more resistance there's less current

  voltage is the same everywhere
• what is Power?

  the rate at which energy is transferred
• what is resistance?


  how hard it is for current to pass through a component in a circuit
• what is direct current?

  only flows in one direction
• what is alternating current?

  constantly changes direction
• what is the UK mains electricity?

  230V
• what is the UK frequency?

  50Hz
• E = P x T
• Q = I x T
• E = Q x V
• V = I x R
• P = I x V
• P = I 2 x R
• what is the power of an electric kettle?

  2760 W
• desrcibe the action of a fuse in a circuit?

  if current is above 5 A

  the fuse melts which breaks the circuit
• name non renewable resources:

  Coal

  oil

  natural gas

  nuclear
• when light intensity increases


  resistance of LDR decreases
• diode


  a non ohmic conductor that allows current to flow in one direction
• why do we get a shock if you touch a live wire

  • we are earthed, 0v
  • the live wire is 230v
  • there is a large potential difference between us and the live wire
  • therefore current flows through our body and gives us a shock
• what is the brown wire?

  • bottom right wire
  • this is the live wire
  • carries current to the appliance
• what is the blue wire?

  • bottom left wire
  • this is the neutral wire
  • carries current away from the appliance
• what is the yellow and green wire?

  • the earth wire
• what is the advantage of a step up transformer emmiting electricity at a high potential difference?

  • reduces current
  • reduces thermal energy transfer to its surroundings
  • which increases the efficiency of power transmissions
• why did a person recieve a fatal shock when the kite was close to the power cable?

  • electric field strength is very high
  • causing the air to become ionised
  • the kite conducts charge to the person
• what does a step down tranformer do?

  • reduces the potential differences to safer levels
  • 230v
  • 50hz