Worksheet Chapter 6: Electricity and Magnetism

1. Explain why electricity is transmitted through the National Grid Network at extremely high voltages (e.g., 132 kV to 500 kV) instead of 240 V.

2. An air conditioner rated at 1500 W (1.5 kW) is used for 8 hours daily throughout a 30-day month. If the electricity tariff is RM 0.30 per kWh (unit): (a) Calculate total electrical energy consumed in kWh. (b) Calculate total cost of electricity for operating the air conditioner that month.

3. True or False: In a 3-pin plug, the fuse is connected directly along the Neutral wire for safety.

4. A homeowner notices that an electric iron with a damaged outer metal body occasionally gives a mild shock when touched. (a) Identify which safety wire in the 3-pin plug is likely faulty or disconnected. (b) Explain how the live wire, earth wire, and fuse work together to protect users from electrocution during a current leak to a metallic casing.

5. Explain the structural differences between a step-up transformer and a step-down transformer in terms of coil turns and voltage output.

6. Fill in the blank: The principle where an electric current is generated in a wire coil cutting across magnetic field lines is called electromagnetic ____________.

7. A transformer has a primary coil with 500 turns and a secondary coil with 100 turns. If the input primary voltage is 240 V a.c., calculate the secondary output voltage.

8. True or False: A transformer can step up or step down the voltage of a direct current (d.c.) supply like a dry cell battery.

9. Which of the following devices is installed in domestic wiring to disconnect electricity supply automatically during a short circuit?

10. State the standard voltage and frequency supplied to domestic residential homes in Malaysia.