Electricity

• What do we mean by the conduction of charge?

  When charges can flow through materials
• What do we mean by insulators?

  Materials that do not let charge flow through them
• What kind of materials are conductors and insulators?


  Metals are good conductors of charge and plastics or rubber are good insulators.
• In electricity, what do we mean by components?


  Any simple electrical device is called a component
• How do we represent circuit components?


  We use symbols to represent components
• How do we represent circuits where components are connected up?


  We use circuit diagrams
• What is a complete circuit?


  When there is an unbroken route from one component to the next and back to the first
• How do we draw circuits?

  We use circuit diagrams and circuit symbols
• What is electric current?

  Current is a flow of electric charge
• What is potential difference?

  Potential difference is the 'push' that make charges flow
• What does current do when it passes through conductors and components?

  Current shifts energy from one component to another
• How do we measure current?

  We measure current with an ammeter
• What is the unit of current?

  The unit of current is Amperes (or Amps for short)
• What is the unit of potential difference?

  The unit of potential difference is the Volt
• What happens to current as it passes around a circuit?

  The current shifts energy, it is not changed
• What is the difference between a series and a parallel circuit?

  A series circuit has only one pathway or loop back to the cells, a parallel circuit has more than one pathway.
• How do bulbs behave in a series circuit?

  In a series circuit, adding another bulb will cause both bulbs to become dimmer and if one bulb is broken, the other does not light up.
• How do bulbs behave in a parallel circuit?

  In a parallel circuit, adding another bulb will cause both bulbs to light up the same as before and if one bulb is broken, the other bulb carries on as normal.
• What happens to current as it travels around a circuit?

  The current shifts energy but it is not used up.
• How does the current behave in a series circuit where there is only one pathway?

  The current is the same in every part of the circuit.
• What happens to the potential difference in a parallel circuit?

  The potential difference supplied by the cell is the same potential difference as that across each component in the parallel circuit.
• What is electrical resistance?

  The wires and the other components in a circuit reduce the flow of charge through them. This is called resistance.
• What is the unit of resistance?

  Ohms
• How does current in a resistor vary as we increase voltage?

  Increasing the voltage will cause the current to increase
• How does electrical resistance affect the current?

  The higher the resistance, the slower the flow of current through the components
• What happens to current in a parallel circuit where there are two pathways?

  The current in each pathway adds up to the current coming from or returning to the cell/battery
• How do we measure potential difference in circuits?

  A voltmeter measures the potential difference in circuits. Voltmeters are connected in parallel in a circuit.
• What happens to the potential difference in a series circuit?

  When cells are connected in series with each other and they are all connected in the same direction, the total potential difference supplied to the circuit is the individual potential differences added together.