electrical energy

• What is the voltage and frequency of the alternating current delivered by the live wire in the UK?

  230V and 50Hz
• What is the primary function of the neutral wire in a household electrical circuit?

  It completes the electrical circuit.
• How does the earth wire prevent electric shock?

  It provides a low-resistance path to the ground.
• What happens when the live wire touches the metal casing of an appliance?

  A surge of current through the earth wire causes the fuse to melt and break the circuit.
• What is the purpose of a fuse in an electrical circuit?

  To melt and break the circuit when the current is too high.
• What is double insulation in electrical appliances?

  It means the appliance has an insulating case that prevents current flow, eliminating the need for an earth wire.
• What is the function of a circuit breaker?

  It automatically breaks the circuit if the current exceeds a certain value.
• What are the advantages of circuit breakers over fuses?

  Circuit breakers do not need replacing and are faster than fuses.
• What are the key differences between direct current (DC) and alternating current (AC)?

  • Direction of current flow:
  • DC flows in one direction
  • AC changes direction periodically
  • Type of source:
  • DC is produced by cells/batteries
  • AC is produced by generators
• What are the roles of the three wires in a three-pin plug system?

  • Live Wire: Delivers AC at 230V and 50Hz
  • Neutral Wire: Completes the electrical circuit
  • Earth Wire: Provides a low-resistance path to the ground
• What is the unit of measurement for current?

  Amperes (A)
• How is current defined in a circuit?


  As the rate of flow of charge at a point in a circuit
• What is the formula for calculating current?

  Current (I) = Charge (Q) / Time (T)
• What is the formula symbol for current?

  I
• What causes current to flow in metals and solutions?


  In metals, it's due to the flow of delocalized electrons; in solutions, it's ions
• What is conventional current?

  The flow of positive charge, opposite to electron flow
• What happens to current after passing through a component in a circuit?

  It remains unchanged because charge is conserved
• How is current measured in a circuit?

  Using an ammeter connected in series
• What is the unit of measurement for potential difference?

  Volts (V)
• How is potential difference defined in a circuit?

  By the work done per unit charge moving between two points
• What is the formula symbol for potential difference?

  V
• What occurs across a component in a circuit regarding potential difference?

  There is a voltage difference as it uses energy
• How is potential difference measured in a circuit?

  Using a voltmeter placed in parallel across the component
• What is the unit of measurement for power?

  Watts (W)
• How is power defined in an electrical context?

  As the rate of energy transferred per unit of time
• What is the formula for calculating power?

  Power (P) = Potential Difference (V) * Current (I)
• What is the unit of measurement for electrical energy?

  Joules (J)
• What does electrical energy represent?

  The energy carried by moving electrons in an electric conductor
• What is the formula symbol for electrical energy?

  E
• What color is the live wire in a plug?

  Brown
• What color is the neutral wire in a plug?

  Blue
• What color is the earth wire in a plug?

  Green and yellow
• What is the potential difference created between the live and neutral wires?

  230V to 0V
• What happens to the earth wire when the live wire touches the metal casing of an appliance?

  The earth wire carries current to the ground.
• Why don't appliances made of insulator materials have the same problem with the earth wire?


  Because they do not conduct electricity.
• What material are wires typically made of?

  Copper
• What material are pins in a plug typically made of?

  Brass
• What is the purpose of wire casings in electrical appliances?

  To act as an electric insulator.
• What happens if a fault develops in an appliance and the live wire touches the outside casing?

  • A large current flows from the live wire to the neutral wire.
  • This causes the fuse to blow, stopping current flow.
• What occurs when someone touches a live wire?

  A big potential difference causes current to flow, resulting in an electric shock.