Mains Electricity

What is the name of the pin labelled 2 in the diagram?

• Earth

• Neutral

• Live

What colour is the Earth wire in a plug?

• Red

• Red and black

• Green

• Green and yellow

Which is the live wire in the diagram?

• Number 2

• Number 3

• Number 4

• Number 5

What is the potential difference of the mains electricity supply? _________ volts

What is the frequency of the mains electricity supply? (do not worry about the units here)

What is the unit of frequency?

What does the graph on the left show?

• direct current

• alternating current

Which diagram shows an oscilloscope trace of alternating current?

• left hand diagram

• right hand diagram

Imagine the diagrams are numbered 1,2,3,4 from left to right.

Which is the symbol for a fuse?

• 1

• 2

• 3

• 4

Imagine the symbols are numbered 1,2,3,4 from left to right.

What is number 3 the symbol for?

• A variable resistor

• A fuse

• A lamp

• A fixed resistor