ELECTRICITY

• A battery is more than one cell
• Match the circuit symbol with its component:

  Ammeter ↔️ A

  Voltmeter ↔️ V

  LED ↔️ Light-emitting diode

  Thermistor ↔️ Resistor dependent on temperature
• In a series circuit, current flows along a single path


  True
• Current is the flow of electrons
• What is the unit of charge?

  Coulombs
• What is the unit of current?

  Amps
• What is the formula for charge?

  $Q =$$I \times t$
• What is the formula for potential difference?

  $V =$$I \times R$
• What is the unit of potential difference?

  Volts
• Potential difference is measured in volts
• Order the steps of how a diode allows current flow

  1️⃣ Direction of current flow matches diode's arrow

  2️⃣ Diode's resistance becomes low

  3️⃣ Current is allowed to flow
• For a resistor at constant temperature, current and potential difference are directly proportional


  True
• A diode allows current to flow in both directions

  False
• What happens to the resistance of a filament bulb as its temperature increases?

  Increases
• A light-dependent resistor (LDR) changes resistance based on the amount of light
• What happens to the resistance of an LDR in bright light?

  Decreases
• In a series circuit, the current is the same at all points

  True
• In a parallel circuit, the total current is the sum of the currents in each branch


  True
• What is the rule for calculating total resistance in a series circuit?

  Add the individual resistances
• What is the formula for calculating total resistance in a parallel circuit?

  $\frac{1}{R_{T}} =$$\frac{1}{R_{1}} +$$\frac{1}{R_{2}}$
• What is the voltage of mains electricity in the UK?

  230 volts
• The live wire in a plug carries the current

  True
• What is the frequency of mains electricity in the UK?

  50 Hertz
• The earth wire is a safety feature in a plug


  True
• What is the formula for power in terms of current and resistance?

  $P =$$I^{2} \times R$
• What is the formula for energy in terms of power and time?

  E = P \times t</latex>
• What is the formula for power in terms of potential difference and current?

  $P =$$V \times I$
• Power is measured in watts
• What is the unit of energy?

  Joules
• The National Grid uses step-up transformers to increase voltage


  True
• Step-down transformers decrease voltage to make it safe for homes

  True
• What happens when two insulators are rubbed together in static electricity?

  Electrons move between them
• Charged objects with the same charge repel each other


  True