Electricity

Question 1

What is electrical charge measured in

Answer 1

Couloms

Question 2

What does 1 Amp of current equal

Answer 2

1 Coulomb of charge per second

Question 3

What is the equation of energy transferred by a component

Answer 3

E = Q x V

Question 4

What is resistance

Answer 4

The potential difference required to drive a current through a component

Question 5

What is resistance measured in

Answer 5

Ohms

Question 6

What is a potential difference / Current graph for an ohmic resistor

Answer 6

It is directly proportional

Question 7

How does current flow in a diode

Answer 7

One direction because a diode has a very high resistance in the reverse direction

Question 8

Why are diodes useful in circuits

Answer 8

Controlling the flow of the current

Question 9

When does an LDR have a high resistance

Answer 9

Dark conditions

Question 10

What are the uses of LDR

Answer 10

Phones and garden lamps

Question 11

What causes the resistance of a thermostat decrease

Answer 11

If the temperature increases

Question 12

What is the equation linking energy, power and time

Answer 12

Energy =power x time

Question 13

What is power in relation to energy

Answer 13

Power is the rate of energy transfer

Question 14

What equation links power, current and resistance

Answer 14

Power = current^2 x resistance

Question 15

What type of current is from a cell

Answer 15

Direct current

Question 16

What is direct current

Answer 16

Current that flows in a single direction

Question 17

What type of current is mains electricity in the UK

Answer 17

Alternating current

Question 18

What is alternating current

Answer 18

Current that is constantly changing direction

Question 19

What is the advantage of alternating current

Answer 19

It is easy to use a transformer which can change the potential difference

Question 20

What is the frequency of alternating current in the UK

Answer 20

50 Hz

Question 21

What’s the potential difference of main electricity

Answer 21

230 V

Question 22

What metal are the three core cables made of and why

Answer 22

Copper as it is a good conductor of electricity

Question 23

What’s the coating of the cable made of and why

Answer 23

Plastic as it doesn’t conduct electricity

Question 24

What’s the name of the brown wire

Answer 24

Live Wire

Question 25

What is the function of the live wire 

Answer 25

It carries the alternating potential difference of 230 V and it is also connected to a fuse in the plug

Question 26

What is the name of the blue wire

Answer 26

Neutral wire

Question 27

What is the function of the neutral wire

Answer 27

It completes the circuit and has a potential difference of 0 V

Question 28

What’s the green yellow wire called

Answer 28

Earth wire

Question 29

What’s the function of the Earth wire

Answer 29

It’s the safety wire to stop the appliance from becoming live

Question 30

What happens when someone touches a live wire

Answer 30

The current will flow through the body into the Earth causing them to be electrocuted

Question 31

What’s the route from a power station to the Home

Answer 31

It goes from the power station to step up transformer to high voltage cables then to step down transformers

Question 32

Why is the energy lost in the power cables

Answer 32

The resistance of wires

Question 33

How can energy loss from power cables be reduced

Answer 33

Building power stations near to homes