An electric heater, Heater A, is used to heat a water bath in a laboratory. It has an electric heating element.
Heater A is designed to operate on the mains supply and is labelled 230 V, 46 W.
What does 46 W tell you about how energy is transferred in the heater?
Heater A has a metal case and an earth connection. Explain how the earth connection protects the user.
Heater B is connected to a low-voltage power supply. It is labelled 12 V, 35 W.
A student says: "I think that both heaters should be fitted with a 3 A fuse."
Use calculations to evaluate this statement.
There is a step-down transformer in the power supply for Heater B. Describe the structure of a step-down transformer.