resistance

• Resistance

  The potential difference required to drive a current through a component
• Resistance of a component

  Determines how much energy is required to drive a current through it
• Low resistance component

  • Requires a small potential difference to drive a current through it
• High resistance component

  • Requires a large potential difference to drive a current through it
• Calculating resistance

  Resistance = Potential difference / Current
• Ohm


  The unit of resistance
• Calculating potential difference

  Potential difference = Current x Resistance
• The equation for resistance is not given in the exam, so it must be learned
• Lamp A

  • Current = 1 A, Potential difference = 1 V, Resistance = 1 Ω
• Lamp B

  • Current = 1 A, Potential difference = 10 V, Resistance = 10 Ω
• The potential difference across a lamp can be calculated using the equation: Potential difference = Current x Resistance