Year 9 Summer 1 - Electricity Part 2

Question 1

Alternating Current (AC)

Answer 1

Current that constantly changes direction.

Question 2

Direct Current (DC)

Answer 2

Current that flows in one direction.

Question 3

Electric field

Answer 3

The area around a charged object where its force can be felt. The field is strongest when close to the charged object.

Question 4

Mains electricity

Answer 4

UK mains electricity is an AC supply (used when plugging appliances in). It is 230V and has a frequency of 50Hz.

Question 5

Static electricity

Answer 5

When two insulating materials are rubbed together, the friction causes electrons to move from one object to the other. The object that loses electrons becomes positively charged. The object that gains electrons becomes negatively charged.

Question 6

Step-down transformer

Answer 6

Used to decrease the potential difference.

Question 7

Step-up transformer

Answer 7

Used to increase the potential difference.

Question 8

What colour is the live wire?

Answer 8

Brown

Question 9

What does the live wire do?

Answer 9

Carries the current from the supply to the appliance.

Question 10

What is the potential difference between the live wire and the earth wire?

Answer 10

230V

Question 11

What colour is the neutral wire?

Answer 11

Blue

Question 12

What does the neutral wire do?

Answer 12

Completes the circuit by carrying the current from the appliance back to the supply.

Question 13

What is the potential difference of the neutral wire?

Answer 13

At or close to 0V.

Question 14

What colour is the earth wire

Answer 14

Green and yellow

Question 15

What is the earth wire?

Answer 15

The safety wire which stops the appliance from going live.

Question 16

What is the potential difference of the earth wire?

Answer 16

0V

Question 17

Does the earth wire carry current?

Answer 17

Only if there is a fault.

Question 18

….. = Potential Difference * Current

Answer 18

Power = Potential difference * Current

Question 19

Power = ….. * Current

Answer 19

Power = Potential Difference * Current

Question 20

Power = Potential Difference * …..

Answer 20

Power = Potential Difference * Current

Question 21

…… = VI

Answer 21

P = VI

Question 22

P = …..

Answer 22

VI

Question 23

What does P stand for?

Answer 23

Power

Question 24

What does V stand for?

Answer 24

Potential Difference

Question 25

What does I stand for?

Answer 25

Current

Question 26

….. = (Current x Current) x Resistance

Answer 26

Power

Question 27

Power = (….. x Current) x Resistance

Answer 27

Current

Question 28

Power = (Current x …..) x Resistance

Answer 28

Current

Question 29

Power = (Current x Current) x …..

Answer 29

Resistance

Question 30

What does R stand for?

Answer 30

Resistance

Question 31

….. = Power x Time

Answer 31

Energy

Question 32

Energy = ….. x Time

Answer 32

Power

Question 33

….. = (I x I)R

Answer 33

P

Question 34

P = (….. x I)R

Answer 34

I

Question 35

P = (I x …..)R

Answer 35

I

Question 36

P = (I x I)…..

Answer 36

R

Question 37

Energy = Power x …..

Answer 37

Time

Question 38

….. = Pt

Answer 38

E

Question 39

E = …..

Answer 39

Pt

Question 40

What does E stand for?

Answer 40

Energy

Question 41

What is the unit for power?

Answer 41

Watts(W)

Question 42

What is the unit for Potential Difference?

Answer 42

Volts(V)

Question 43

What is the unit for current?

Answer 43

Amperes/Amps(A)

Question 44

What is the unit for resistance?

Answer 44

Ohms(Omega)

Question 45

What is the unit for energy?

Answer 45

Joules(J)

Question 46

What is the unit for time?

Answer 46

Seconds(s)

Question 47

The National Grid

Answer 47

A system of cables and transformers linking power stations to consumers.

Question 48

What is electrical power transferred through to get from power stations to consumers?

Answer 48

The National Grid

Question 49

Why is The National Grid an efficient way to transfer energy?

Answer 49

It reduces heating losses.

Question 50

What happens when two electrically charged objects are brought close together?

Answer 50

They exert a force on each other.

Question 51

What do two objects that carry the same amount of charge do?

Answer 51

Repel

Question 52

What do two objects that carry different types of charge do?

Answer 52

Attract

Question 53

Is attraction and repulsion between two charged objects a contact or non-contact force?

Answer 53

Non-contact