Question 1: Define electrical power in the context of mains electricity.

Answer: Electrical power is the rate at which electrical energy is transferred or converted in a circuit, measured in watts (W).

Question 2: Explain how voltage and current influence the power consumed by an electrical appliance.

Answer: Power is directly proportional to both voltage and current; increasing either increases the power consumption, as described by the equation P = V × I.

Question 1: A kettle operates at a voltage of 230 V and draws a current of 13 A. Calculate its power consumption in watts.

Answer: Power = Voltage × Current = 230 V × 13 A = 2990 W

Question 2: An appliance has a power rating of 1500 W and is connected to a 230 V supply. Find the current drawn by the appliance.

Answer: Current = Power / Voltage = 1500 W / 230 V ≈ 6.52 A

Question 3: A device consumes 7200 J of energy in 2 hours. Calculate its average power usage in watts.

Answer: Power = Energy / Time = 7200 J / (2 × 3600 s) = 7200 / 7200 = 1 W

Question 1: Identify three safety precautions that must be considered when designing circuits for high-power household appliances.

Answer: Use appropriate fuse ratings, ensure wiring is capable of handling maximum current, and include proper insulation and earthing to prevent shocks and fires.

Question 1: In a household, a 1000 W microwave oven and a 1500 W kettle are plugged into the same circuit. If the circuit's maximum current capacity is 10 A at 230 V, assess whether the circuit can handle both appliances operating simultaneously. Show your calculations.

Answer: Total power = 1000 W + 1500 W = 2500 W. Total current = Power / Voltage = 2500 W / 230 V ≈ 10.87 A. Since this exceeds the circuit's capacity of 10 A, both appliances cannot be used simultaneously without risking overload.

Question 1: Describe how power calculations influence the design of energy-efficient household appliances and the importance of selecting appropriate voltage and current ratings.

Answer: Power calculations help manufacturers optimise energy consumption, ensuring appliances meet safety standards and are energy-efficient. Selecting appropriate voltage and current ratings prevents overloading, reduces energy waste, and prolongs appliance lifespan.