P5 Electricity in the home Flashcards
What is direct current?
Current that passes round the circuit in one direction only
What is alternating current?
Current that repeatedly reverses its direction
What is the frequency of the UK mains supply?
50 Hertz
What is the equation for frequency?
frequency = 1/time taken for one cycle
What is the national grid?
A system of cables and transformers linking power stations to consumers
What do step-up transformers do?
Used to increase the p.d from the power station to the transmission cables
What do step-down transformers do?
Used to decrease the p.d for domestic use
Why is the outer cover of a three-pin plug and the outer casing of sockets made from a stiff plastic material?
Because it is a good insulator
Why are the pins of the plug made of brass?
Because it is a good electrical conductor, it is hard and it will not rust or oxidise
What colour is the earth wire?
Striped green and yellow
What colour is the live wire?
Brown
What colour is the neutral wire?
Blue
Where would you find the fuse in a plug?
Between the live pin and the live wire
Why must appliances with a metal case be earthed?
Because it stops the metal case becoming live
What is the equation involving power, energy and time?
Power (W) = Energy (J)/time(s)
