P5 - Mains Electricity Flashcards
What is direct current?
Current that flows in one direction.
What is alternating current?
Current that repeatedly reverses direction
What is the frequency of alternating current?
50Hz
What does the frequency tell us?
How many times a current changes direction in 1 second.
What are the 3 equations for power?
P=E/T and P=IV and P=I^2R
what is a fuses job?
to prevent fires
what is the colour of the live wire?
brown
what is the voltage of the live wire?
230 volts
what wire is the blue one?
the neutral wire (colour of water - neutral )
what colour is the earth wire?
green ( colour of nature - green )
why are pins on a plug made from brass?
as it conduct electricity and is very rigid
which of the three pins on a plug are earthed and what does it mean?
the top one and earthed means if the live wire comes into contact with casing, the curent will flow through earth wire.
why does the thin wire in a toaster get very hot when on?
electrons are forced around the wire by potential difference ans since the wire is very thin, there is less space for electons to move, and will therefore increase the amount of collisions with the ions in the wire and therfore increase the temperatue.
what is the mains voltage in the UK?
230 volts
what is the maximum and minimum volatage of alternating current?
maximum = 325v and minimum = -325
