A commercial espresso machine has an electric boiler heating element and a rotary water pump motor.
The resistance of the heating element is 18 Ω18\ \Omega18 Ω.
The mains voltage is 230 V230\text{ V}230 V.
State the equation linking voltage, current, and resistance.
Show that the current in the heating element is about 12.8 A12.8\text{ A}12.8 A when it is working.
The espresso machine is fitted with a fuse rated at 15 A15\text{ A}15 A.
Explain why the espresso machine is fitted with a fuse.
When the water pump motor is working, the current in it is 1.8 A1.8\text{ A}1.8 A.
Explain why it would not be sensible to replace the 15 A15\text{ A}15 A fuse with a 10 A10\text{ A}10 A fuse.
28 exam-style questions on Edexcel IGCSE Physics Mains electricity. Each one has a worked solution and a mark scheme showing where the marks go.