Mains (P1)

Question 1

What type of case does a plug have and why?

Answer 1

Plastic because it is an insulator and doesn’t conduct any electricity

Question 2

Earth, neutral and live wire colours

Answer 2

Earth green and yellow
Neutral blue
Live brown

Question 3

National grid

Answer 3

A system of cables linking power stations to consumers

Question 4

Step-up vs step-down transformer

Answer 4

Step-up increases p.d. Step-down the opposite

Question 5

Power station, pylon, customer p.d.

Answer 5

Power station up to 12kV pylons, up to 400kV, consumer 230V

Question 6

Why do they use transformers?

Answer 6

Higher potential difference= less current
Lower current means less heating of the power lines, wasting less energy
More efficient

Question 7

Overhead + and -

Answer 7

Easier to fix
Cheaper
Cooled by air
More prone to breaking

Question 8

Underground + and -

Answer 8

Less prone to breaking
Hold heat insulated by ground
Hard to fix

Question 9

Why do we use a parallel circuit in the home

Answer 9

Each can be operated independently

Question 10

Facts

Answer 10

325 peak voltage
12 v rating
50 hz frequency
AC Flow

Question 11

Wire functions

Answer 11

Live carries current to the appliance
Neutral carries current away
Earth carries current if the live makes contact with the metal casing to save us, contains protective circuit breaker

Question 12

Plug

Answer 12

Cable grip at the bottom holds the cable in place

Neutral on the left, earth central, live right, fuse on the right side of that

Question 13

p.d. of live wire

Answer 13

220