8.1 Basic principles of electricity Flashcards Preview

C08. Electrical safety and Electrical at Work Regulations 1989 > 8.1 Basic principles of electricity > Flashcards

Flashcards in 8.1 Basic principles of electricity Deck (11)
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1

Electricity is energy made available by

the flow of electrons through a conductor

2

Atoms consist of

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

3

movement of electrons from atom to atom is known as

electron flow

4

Electron flow along a conductor is called

current

5

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

amperes (amps) (symbol I).

6

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

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

7

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

ohms (Ω) (symbol R).

8

Ohms law –

V = I × RI = V/RR = V/I

9

Mains electricity is from an ___________________ supply

alternating current (AC)

10

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

230V 50 Hertz (Hz).

11

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

650V AC