Domestic Uses & Safety

Subdecks (2)

Cards (60)

  • Explain why the student should open the switch after each reading.
    resistor would get hot if current left on
    so its resistance would increase
  • Why does the hairdryer not need an earth wire?

    case is plastic
  • What is meant by specific latent heat of fusion?
    amount of energy required to change the substance from solid to a liquid and has a unit mass
  • Describe the action and purpose of a solar panel.
    water heated by radiation
    water used to heat buildings
  • A fuse is connected in the live wire.
  • RCCBs are sometimes preferred to fuses because they react faster
  • The two wires are the live and neutral wires.
  • What do the letters a.c. stand for?
    alternating current
  • Describe the advantages and disadvantages of keeping the road clear of ice using
    energy storage
    salt
    undersoil electrical heating
  • energy storage advantages
    no fuel costs
    no environmental effects
  • disadvantages
    -expensive to set up and maintain
    -need to dig deep under road
  • salt spreading advantages
    easily available
    cheap
  • Salt spreading disadvantages
    can damage trees
    needs to be cleaned away
  • undersoil heating advantages

    not dependent on weather
    can be switched on and off
  • undersoil heating disadvantages:
    costly
    bad for environment
  • mains electricty is what type of supply
    AC supply
  • UK Frequency of AC
    50Hz (hertz)
  • UK voltage of AC
    230V
  • What is alternating current

    It comes from the mains. The current continuously varies, from positive to negative(charges changes direction)
  • What is direct current?
    The movement of charge in one direction only- cells and batteries provide this
  • How many wires in a plug
    3 wires
  • Live wire colour
    Brown
  • Live wire voltage

    230V
  • Purpose of live wire
    carries alternating p.d from the supply
  • Why is the live wire dangerous?

    our bodies are at 0 V. If you were to touch a live wire, a big potential difference will act across your body, causing a current to flow through you. this causes a large electric shock which could injure or even kill you. And even if the mains circuit is off, current may still be flowing through it
  • Neutral wire colour

    Blue
  • Neutral wire voltage

    0V
  • Neutral wire purpose
    Completes the circuit
  • Earth wire colour

    Green and yellow stripes
  • Earth wire voltage
    0V
  • Purpose of earth wire
    It only carries a current if there is a fault, it is a safety wire to stop the appliance becoming live
  • Electrical energy transfer examples
    Kinetic energy for a motor and thermal energy in a kettle
  • Work done is equal to
    Energy trasnferred
  • Greater power rating means....
    More energy used
  • What is the national grid
    A system of cables and transformers linking [power stations to consumers across the UK
  • What is transferred from power stations to consumers using the national grid
    Electrical power
  • What do transformers to
    Change the potential difference
  • What do step up transformers do

    Increase the pd from the power station to the national grid
  • Why do step up transformers increase the pid
    As the power is constant, current decreases so less energy is lost
  • What do step down transformers do
    Decrease the pd from the national grid to consumers