Household Electricity
AC mains alternate direction many times per second.
About this topic
Mains electricity is alternating current (AC), reversing direction 50 or 60 times each second, at about 230 V (UK/Europe) or 120 V (US). AC is easy to transform to different voltages for efficient long-distance transmission.
Plugs have live, neutral and earth wires, and fuses in the live wire protect appliances. The RMS value of AC gives the same heating as a DC voltage of that size; the peak of 230 V mains is actually about 325 V. Home circuits are wired in parallel, and a ring main or radial circuit supplies sockets, with separate circuits for lights and high-power appliances such as cookers.
Electricity meters record energy in kilowatt-hours, and a typical home might use 10 kWh in a day. Choosing efficient appliances reduces both bills and carbon emissions.
Students often think AC electrons travel all the way from the power station. In fact they just vibrate back and forth a tiny distance; it is the energy in the fields that travels. The switch and fuse always go in the live wire so that appliances are dead when switched off.
Key ideas
- Frequency is 50 or 60 Hz
- Voltage is 120 or 230 V
- Transformers change voltage
Quick check
Use cases: where Household Electricity helps
- Homework: review the key idea behind Household Electricity before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Household Electricity without notes.
- Visual learning: play with the interactive lab to see how Household Electricity changes when you adjust its inputs.
- Teaching a friend: explain Household Electricity in your own words, then compare your version with the key ideas.
The same laws describe car crashes, sports, satellites and everyday machines.
Frequently asked questions
What is Household Electricity?
AC mains alternate direction many times per second.
What will I learn in Household Electricity?
Frequency is 50 or 60 Hz. Voltage is 120 or 230 V. Transformers change voltage.
Is Household Electricity part of Physics?
Yes. It is one of 150 Physics topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Household Electricity lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Household Electricity?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.