2.3.2 Mains Electricity

• Which type of current is less efficient for long-distance transmission?

  Direct current (DC)
• The voltage of direct current alternates between positive and negative.

  False
• Alternating current is more efficient for long-distance transmission
• Direct current changes direction periodically.

  False
• The neutral wire in a mains plug is colored blue
• The live wire carries the alternating current voltage from the source.


  True
• The three main wires in a mains electrical system are live, neutral, and earth wires.


  True
• The neutral wire returns the current to the power source, completing the circuit.


  True
• What type of current is mains electricity in the UK?

  Alternating current (AC)
• The frequency of mains electricity in the UK is 50 hertz
• Direct current flows in one direction only.


  True
• The UK mains voltage is 230 volts
• What are common sources of direct current?

  Batteries, solar cells
• What is the voltage of AC mains electricity in the UK?

  230 volts
• Order the pins of a mains plug according to their color and function:

  1️⃣ Live (Brown) - Carries AC voltage

  2️⃣ Neutral (Blue) - Completes the circuit

  3️⃣ Earth (Green and Yellow) - Provides a safety path
• What is the purpose of the earth pin in a mains plug?

  Prevents electric shock
• The neutral wire returns the current to the power source
• The earth pin is a safety feature that connects the appliance to the ground
• The live wire carries the voltage
• Match the wire with its function:

  Live Wire ↔️ Carries voltage to appliance

  Neutral Wire ↔️ Completes the circuit

  Earth Wire ↔️ Provides path to ground
• Mains electricity in the UK is an alternating current (AC) supply, unlike direct current (DC) which flows in one direction
• DC electricity flows in a constant direction.


  True
• In AC electricity, the voltage alternates between positive and negative
• Why is AC electricity preferred for long-distance transmission?

  Can be stepped up/down
• The live wire carries electricity from the power source to the appliance
• Steps to ensure safety when using electrical appliances

  1️⃣ Regular maintenance of appliances

  2️⃣ Avoid overloading circuits

  3️⃣ Ensure earth wires are connected

  4️⃣ Keep devices away from water
• Match the electrical component with its symbol and description:

  Resistor ↔️ Restricts current, dissipates heat

  Capacitor ↔️ Stores electrical energy

  Inductor ↔️ Stores energy in magnetic field
• Why is understanding electrical symbols crucial in domestic circuit diagrams?

  For reading and interpreting plans
• A capacitor stores electrical energy in a magnetic field.

  False
• In a series circuit, components form a single path for the current
• Mains electricity in the UK is an alternating current with a frequency of 50 hertz.
• What is the voltage of UK mains electricity?

  230 volts
• The live pin in a mains plug is colored blue.

  False
• Match the pin color with its function:

  Brown ↔️ Live

  Blue ↔️ Neutral

  Green and Yellow ↔️ Earth
• What is the primary function of the live wire in a mains electrical system?

  Carries AC voltage
• The earth wire provides a safe path for current during a fault.


  True
• Match the electrical component with its description:

  Resistor ↔️ Restricts current flow

  Capacitor ↔️ Stores energy in electric field

  Inductor ↔️ Stores energy in magnetic field

  Switch ↔️ Controls current flow
• In a parallel circuit, voltage is divided across all components.

  False
• What happens to a fuse when the current exceeds a safe level?

  The wire melts
• Order the features of RCDs, fuses, and circuit breakers based on their operation:

  1️⃣ RCD detects current imbalance

  2️⃣ Fuse melts to break circuit

  3️⃣ Circuit breaker switches off and can be reset