P5 Electricity in the Home (paper 1)

Question 1

What are the two types of current

Answer 1

Alternating current
Direct current

Question 2

What type of current is the main

Answer 2

Alternating

Question 3

What does DC stand for

Answer 3

Direct current

Question 4

What does AC stand for

Answer 4

Alternating current

Question 5

Where will you find direct current

Answer 5

A cell or battery

Question 6

What is direct current

Answer 6

current that flows in one direction, it is either positive or negative and found in batteries and cells

Question 7

What would an oscilloscope graph look like for direct current

Answer 7

A straight line

Question 8

What is the voltage for the mains supply

Answer 8

230V

Question 9

What is the frequency for the mains supply

Answer 9

50Hz

Question 10

What is alternating current

Answer 10

A current where the electrons move in alternating directions while moving around the circuit, fluctuating 50 times per second between positive or negative

Question 11

What would an oscilloscope graph of alternating current look like

Answer 11

A wiggly line going above and below the 0V line

Question 12

What colour is the live wire

Answer 12

brown

Question 13

What is the live wire

Answer 13

The wire which the electricity enters the appliance though, after the fuse

Question 14

What colour is the neutral wire

Answer 14

blue

Question 15

What is the neutral wire

Answer 15

It is the wire that completes the circuit, the current comes back into the plug through it

Question 16

What colour is the earth wire

Answer 16

Yellow and green

Question 17

What is the earth wire

Answer 17

it is the safety wire, making appliances safer to touch

Question 18

When is the earth wire needed

Answer 18

For appliances with metal casing

Question 19

How does the earth wire make appliances safer

Answer 19

• the earth wire carries free electrons (in the appliances metal casing) down to earth
• the prevents electric shocks and does not affect the circuit

Question 20

What is A

Answer 20

The live wire

Question 21

What is B

Answer 21

Fuse

Question 22

What is C

Answer 22

Cable grip

Question 23

What is D

Answer 23

Outer insulation

Question 24

What is E

Answer 24

Neutral wire

Question 25

What is F

Answer 25

earth wire

Question 26

What is the core of a wire made from

Answer 26

Copper

Question 27

What insulator do the wires have

Answer 27

A coloured plastic coating

Question 28

Why is the cable surrounded by rubber

Answer 28

Because rubber is an insulator and makes it safe to touch

Question 29

Why does the plug have a plastic coating

Answer 29

To insulate the plug making it safe to touch

Question 30

What is the purpose of a fuse

Answer 30

A fuse is a thin wire that will melt from the heating affect of the current, to stop the circuit

Question 31

What is a disadvantage of a fuse

Answer 31

It cannot be reused

Question 32

What is the advantage of a circuit breaker

Answer 32

It can be used again and again

Question 33

What does energy transferred depend on

Answer 33

power

Question 34

What are the three power equations

Answer 34

P = energy / time P = current^2 x resistance P = current x voltage

Question 35

Define potential difference (voltage)

Answer 35

voltage is the amount of energy carried per charge

Question 36

Define current

Answer 36

The rate of flow of charge

Question 37

What is the national grid

Answer 37

It is a giant system of cables and transformers that covers the UK and connects power stations to consumers

Question 38

What is the potential difference like in the national grid

Answer 38

High

Question 39

What is the current like in the national grid

Answer 39

Low

Question 40

What do step up transformers do

Answer 40

Increase the voltage to 400,000V

Question 41

What do step down transformers do

Answer 41

Decrease the voltage to 230V

Question 42

Why do power stations run below their maximum power output

Answer 42

So there's space capacity to cope with a high demand

Question 43

Why does the national grid have a low current

Answer 43

To keep the heating affect as low as possible so no energy is wasted

Question 44

Why is there a step down trasformer

Answer 44

So that electricity is safer to use and so it doesn't blow the appliances

Question 45

Are transformers efficient prove it

Answer 45

Yes power in primary coil = power in secondary coil

Question 46

What is the average voltage for DC

Answer 46

1.5V

Question 47

Why are the pins on a plug made of Brass

Answer 47

- it is difficult to bend ~ strong - very good electric conductor