An electric shower uses about 9000 W — that's 9000 joules EVERY SECOND! A 10-minute shower transfers 5.4 million joules. Meanwhile, your phone charger at 5 W uses just 5 joules per second. Leave it plugged in all day (86,400 seconds) and it transfers only 432,000 joules — less than a tenth of one shower! This is why power ratings matter for electricity bills. High power appliances used frequently are what cost you money.
This introduction covers The Expensive Shower within Electrical Power & Energy for GCSE Physics. Revise Electrical Power & Energy in Electricity for GCSE Physics with 15 exam-style questions and 30 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 1 of 15 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Electrical Power & Energy
What is the unit of electrical power?
A television has a power rating of 120 W and is left on for 3 hours. Calculate the energy transferred by the television in this time. Use the equation: energy transferred = power x time. Give your answer in joules.
Quick recall flashcards
Unit of power?
Watt (W) or joules per second (J/s)
What is 1 watt?
1 joule of energy transferred per second (1 W = 1 J/s)