v=ir

• What are the two types of electrical current?

  Direct and alternating current
• What is resistance in an electrical component?

  • Opposition to the movement of electrical charge
  • Measured in ohms (Ω)
• What is the unit of resistance?


  Ohms (Ω)
• What does potential difference measure in a circuit?

  It measures the energy given to the charge carriers in a circuit
• What is the unit of potential difference?

  Volts (V)
• How is potential difference measured across a component?

  By placing a voltmeter in parallel with that component
• What is the relationship between potential difference, energy, and charge?

  Potential difference is the energy transferred per unit of charge
• How can potential difference be calculated using energy and charge?


  Using the equation \(V = \frac{E}{Q}\)
• What does a potential difference of 1 volt mean?

  1 joule of work is done per coulomb of charge
• What is the potential difference if 2 C of charge shifts 4 J of energy?

  2 V
• How much energy is transferred when 3 C of charge moves through a potential difference of 6 V?

  18 J
• What is the equation for potential difference in terms of current and resistance?

  Potential difference = current × resistance
• What is the unit of current?

  Amps (A)
• What is the potential difference if a current of 2 A flows through a resistance of 40 Ω?

  80 V
• What is the resistance of a component if 12 V causes a current of 2 A through it?

  6 Ω
• What are the key facts about conductors and insulators regarding resistance?

  • Conductors have a low resistance
  • Insulators have a high resistance