Domestic electricity and safetyIB MYP Physics: Flashcards

What these 14 flashcards ask

What is the mains voltage and frequency in the UAE?
What does a frequency of 50 Hz mean?
What is the difference between a.c. and d.c.?
Which type of current does a cell supply?
What colour is the live wire?
What colour is the neutral wire?
What colour is the earth wire?
In which wire is the fuse fitted?
How does a fuse work?
How do you choose the rating of a fuse?
Give two advantages of a circuit breaker over a fuse.
Why is a metal casing earthed?
What is double insulation?
Why are water and electricity a dangerous mix?

Exam questions on Domestic electricity and safety

A family in Abu Dhabi buys an electric kettle with a metal casing. The kettle has a three-pin plug fitted with a fuse and is connected to the mains supply.
Explain why the metal casing of the kettle is connected to the earth wire.2 marks
A hair salon in Dubai uses a hairdryer that normally draws a current of 8 A from the 230 V mains supply. The plug can be fitted with a 1 A, 3 A, 5 A or 13 A fuse.
Explain how a fuse protects the hairdryer circuit.2 marks
A school workshop in Singapore has a power drill with a plastic casing and a two-core cable with no earth wire. The workshop's consumer unit (fuse board) uses circuit breakers instead of fuses.
Explain how double insulation protects the user of the drill even though it has no earth wire.3 marks

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).