Electricty Y7 Physics

• Electricity is a flow of charges. Electricity can flow through conductors but not through

  insulators. Metals are good conductors of electricity. Plastics are good insulators.
• Charge = Current x Time
• Current is the amount of electricity flowing in the circuit.

  ● It is measured using an ammeter connected in series.

  ● The units for current are amps (A).
• Voltage provides the ‘push’ and energy.

  ● It is measured using a voltmeter connected in parallel.

  ● The units are volts (V)
• The resistance of a circuit is a way of saying how easy or difficult it is for electricity to flow.

  ● High resistance = hard for electricity to flow = small current.

  ● Low resistance = easy for electricity to flow = large current
• Thin wires and resistors have high resistances. Thick wires have low resistances.
• Circuits can be series or parallel circuits.
• Fuses are used in plugs. They melt if the current gets too high. A fuse has a rating that shows

  what current it can carry without melting. It is important to use the correct fuse.
• Circuit breakers also cut off the current if it gets too high. They protect the ring mains in

  buildings (loops of parallel circuits).
• Cables have three colour-coded inner wires. The live and neutral wires are part of the circuit.

  The earth wire works with the fuse for safety
• Circuit breakers also cut off the current if it gets too high. They protect the ring mains in

  buildings (loops of parallel circuits).
• Cables have three colour-coded inner wires. The live and neutral wires are part of the circuit.

  The earth wire works with the fuse for safety