8.1 Basic principles of electricity

Question 1

Electricity is energy made available by

Answer 1

the flow of electrons through a conductor

Question 2

Atoms consist of

Answer 2

a central nucleus made up of protons and neutrons, which is orbited by rings of electrons.

Question 3

movement of electrons from atom to atom is known as

Answer 3

electron flow

Question 4

Electron flow along a conductor is called

Answer 4

current

Question 5

The current or rate of electron flow (numbers of electrons passing a point per second) is measured in

Answer 5

amperes (amps) (symbol I).

Question 6

The difference in positive and negative potential between the terminals of a power supply (potential difference) is measured in

Answer 6

units of volts (symbol V). Higher voltage results in greater current flow.

Question 7

All materials, including conductors, will afford some resistance to the flow of electrons. The resistance of a conductor is measured in

Answer 7

ohms (Ω) (symbol R).

Question 8

Ohms law –

Answer 8

V = I × RI = V/RR = V/I

Question 9

Mains electricity is from an ___________________ supply

Answer 9

alternating current (AC)

Question 10

Mains electricity in the UK is a ?V supply, at a frequency of ? Hertz (Hz).

Answer 10

230V 50 Hertz (Hz).

Question 11

High voltage is defined in the HSE guidance Electricity at work: Safe working practices (HSG85) as being in excess of

Answer 11

650V AC