Question 1: Define electrical power and state its SI unit.

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

Question 2: Explain how the power dissipated in a resistor relates to current and voltage.

Answer: The power dissipated in a resistor is given by P = VI, where V is the voltage across it and I is the current flowing through it.

Question 1: A household kettle uses a power of 3 kW when operating at a voltage of 230 V. Calculate the current drawn by the kettle.

Answer: I = P / V = 3000 W / 230 V ≈ 13.04 A

Question 2: An electric heater has a current of 10 A and operates at 230 V. Calculate its power consumption.

Answer: P = VI = 230 V × 10 A = 2300 W

Question 3: A solar-powered village uses a 5 kW photovoltaic system. If the system operates at an average voltage of 250 V, what is the average current supplied?

Answer: I = P / V = 5000 W / 250 V = 20 A

Question 1: List three safety precautions to consider when installing electrical equipment outdoors to minimise environmental impact.

Answer: Ensure proper grounding to prevent electrical hazards, use weatherproof enclosures to avoid environmental damage, and verify that wiring complies with safety standards to prevent leaks and fire hazards.

Question 1: A community uses a 10 kW wind turbine to generate electricity. If the turbine operates at an average power of 8 kW during peak wind conditions for 5 hours, estimate the total energy produced in kilowatt-hours (kWh).

Answer: Energy = Power × Time = 8 kW × 5 h = 40 kWh

Question 1: A new eco-friendly washing machine has a power rating of 2.5 kW. If it is used for 1.5 hours daily, calculate the total energy consumption in a month (30 days).

Answer: Total energy = Power × Time per day × Number of days = 2.5 kW × 1.5 h × 30 = 112.5 kWh

Question 2: Discuss how increasing the efficiency of electrical appliances can contribute to reducing environmental impact, referencing power equations.

Answer: Increasing the efficiency of electrical appliances reduces the amount of power wasted as heat, meaning less energy is needed to perform the same task. Since power equations relate power to current and voltage, more efficient appliances draw less current or operate at lower voltages for the same power output, reducing energy consumption. This decrease in energy use lowers greenhouse gas emissions from power plants, contributing to a more sustainable environment.

Question 1: Describe how power management in smart grids utilises power equations to optimise energy distribution and reduce environmental impact.

Answer: Smart grids use power equations to monitor and control electricity flow, ensuring that energy is distributed efficiently. By calculating the power consumption of different devices, the grid can prioritise renewable sources, minimise waste, and balance load demands, all of which reduce reliance on fossil fuels and lower emissions.