Question 1: Define the function of the Live wire in mains electricity systems.

Answer: The Live wire carries the alternating current from the power supply to the appliance, providing the voltage difference needed for current flow.

Question 2: Explain why the Neutral wire is essential in completing the electrical circuit.

Answer: The Neutral wire provides a return path for the current, completing the circuit back to the power supply and maintaining safety and efficiency.

Question 3: Describe the purpose of the Earth wire in household electrical systems.

Answer: The Earth wire provides a safety path to prevent electric shocks by directing any fault current safely into the ground.

Question 4: How does the potential difference between Live and Neutral wires affect appliances?

Answer: The potential difference causes current to flow through the appliance, enabling it to operate.

Question 1: Calculate the current flowing through an appliance rated at 2400 W connected to a 230 V mains supply. (Use the formula I = P / V)

Answer: I = 2400 W / 230 V = approximately 10.43 A

Question 2: If a fault causes a 50 A current to flow into the Earth wire, and the wire's resistance is negligible, explain why the circuit breaker trips immediately. (Answer in 2-3 sentences.)

Answer: The circuit breaker trips because the high fault current exceeds the safe limit, causing it to disconnect the circuit to prevent electric shocks or fires.

Question 1: Identify two safety precautions engineers should consider when designing electrical systems involving Live, Neutral, and Earth wires.

Answer: Ensuring proper grounding of the Earth wire and using circuit breakers to disconnect power during faults are essential safety precautions.

Question 2: Describe a scenario in industrial engineering where improper wiring of Live and Neutral could cause safety hazards.

Answer: If the Live wire is connected to a component designed for Neutral, it could cause electric shocks during maintenance. Additionally, improper wiring can lead to short circuits, overheating, or fires, posing serious safety risks.

Question 1: A household circuit supplies 230 V and has a circuit breaker rated at 16 A. The wiring used is copper with a resistance of 0.02 Ω per metre. If the circuit length is 20 metres, calculate the voltage drop across the wiring. (Use V_drop = I × R_total, where R_total = resistance per metre × length).

Answer: Total resistance R_total = 0.02 Ω/m × 20 m = 0.4 Ω; Current I = 16 A; Voltage drop V_drop = 16 A × 0.4 Ω = 6.4 V.

Question 1: Explain how the roles of Live, Neutral, and Earth wires contribute to both the functionality and safety of an electrical appliance in a household setting. Include in your answer the importance of proper wiring and safety devices such as circuit breakers.

Answer: The Live wire supplies voltage and current to the appliance, enabling operation. The Neutral wire completes the circuit by providing a return path, maintaining a safe and balanced system. The Earth wire acts as a safety measure by directing fault currents safely into the ground, preventing electric shocks. Proper wiring ensures that these functions are correctly implemented, and safety devices like circuit breakers protect against overloads and faults, reducing the risk of fires and electric shocks.