1. Power is a measure of how quickly energy is transferred. The unit of power is the watt, W. The more energy that is transferred in a certain time, the greater the power. A 100 W light bulb transfers more electrical energy each second than a 60 W light bulb.

2. Power is a calculated by using this equation: For example, what is the power of a 5 A, 1.5 V lamp? Power = 5 × 1.5 = 7.5 W

5. Fuses restrict current. Fuses come in standard ratings of 3 A, 5 A or 13 A. Multi-boxes have fuses to restrict the current that flows into them – otherwise, they will overheat and blow up!

6. Fuses blow if the current they restrict is exceeded – avoiding the multi-box from blowing up! Which fuse should be used for a multi-box with a 1,150 W heater and a 50 W lamp plugged into it? The multi-box is plugged into the mains (240 V). The circuit is parallel.

7. Which fuse should be used for a multi-box with a 1,150 W heater and a 50 W lamp plugged into it? The multi-box is plugged into the mains (240 V). = 5.0 A - Therefore use the 13A fuse.