# Topic 12 & 13 Magnetism, motor effect & EM induction Flashcards Preview

## Edexcel GCSE Physics > Topic 12 & 13 Magnetism, motor effect & EM induction > Flashcards

Flashcards in Topic 12 & 13 Magnetism, motor effect & EM induction Deck (50)
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1
Q

1 What are the two ends of a bar magnet called?

A

north-seeking pole and south-seeking pole, or just north pole and south pole

2
Q

2 Name two magnetic materials.

A

any two from iron, cobalt, nickel, steel

3
Q

3 What happens if you arrange two magnets with their north poles close to each other?

A

They repel each other.

4
Q

4 How can you arrange two magnets so they attract each other?

A

put opposite poles close to each other/put a north pole near a south pole

5
Q

5 What is a magnetic field?

A

the space around a magnet which affects magnetic materials

6
Q

6 How can you find the shape of a magnetic field?

A

use iron filings or plotting compasses

7
Q

7 Name two electrical devices that use magnets.

A

any two from motors, loudspeakers, generators

8
Q

8 Why do compasses point north?

A

The Earth has a magnetic field.

9
Q

9 Describe the shape of the Earth?s magnetic field.

A

similar to the field of a bar magnet

10
Q

10 Why are compass needles weighted at one end?

A

In most places the Earth’s magnetic field is not parallel to the surface.

11
Q

11 Which part of the Earth is responsible for the Earth?s magnetic field?

A

outer core

12
Q

12 What is the difference between the Earth?s north magnetic pole and its North Pole?

A

The Earth spins around an axis through the North Pole; the north magnetic pole is where compasses point to.

13
Q

13 What is an induced magnet?

A

something that is a magnet only because it is in the magnetic field of another magnet

14
Q

14 Name two materials that an induced magnet could be made from.

A

any two from iron, cobalt, nickel, steel

15
Q

15 You are using plotting compasses to find the shape of the magnetic field of a bar magnet. Which way does the needle point?

A

away from the north pole/towards the south pole

16
Q

16 How does a magnetic field diagram show where the field is strongest?

A

strongest where the lines are closest together

17
Q

17 What is a uniform magnetic field?

A

a field with the same strength and direction everywhere

18
Q

18 How can you produce a uniform magnetic field?

A

using two flat magnets

19
Q

19 What is the shape of the magnetic field around a wire with a current flowing through it?

A

circular around the wire

20
Q

20 What is an electromagnet?

A

a magnet made when current flows through a coil of wire

21
Q

21 How can you create a magnetic field around a wire?

A

pass a current through it

22
Q

22 Where is the magnetic field of a wire strongest?

A

close to the wire

23
Q

23 How can you increase the strength of the field around a wire?

A

increase the current

24
Q

24 How can you change the direction of the field around a wire?

A

change the direction of the current

25
Q

25 What is a solenoid?

A

a coil of wire with a current flowing through it/another name for an electromagnet

26
Q

26 Why is an electromagnet called a temporary magnet?

A

It is only magnetic when a current is flowing.

27
Q

27 Describe the magnetic field inside a solenoid.

A

uniform, along the centre of the coil

28
Q

28 Why is the magnetic field of a solenoid stronger inside the coil than outside it?

A

The fields from the two halves of the coil reinforce each other in the middle and partially cancel each other out outside it .

29
Q

29 Describe the magnetic field between two flat magnets.

A

uniform, has the same strength and direction everywhere

30
Q

30 What is the motor effect?

A

a force produced when a current flows in a magnetic field

31
Q

31 How can you make a magnetic field around a wire?

A

pass a current through the wire

32
Q

32 Where is the magnetic field of a wire strongest?

A

close to the wire

33
Q

33 How can you increase the strength of the field around a wire?

A

increase the current

34
Q

34 What is a solenoid?

A

a coil of wire with a current flowing through it/another name for an electromagnet

35
Q

35 Why is an electromagnet called a temporary magnet?

A

it is only magnetic when a current is flowing

36
Q

36 Give two ways of increasing the strength of the motor effect

A

increase the current, use a stronger magnetic field

37
Q

37 What does Fleming?s left-hand rule help you to work out?

A

the direction of the force produced when a current flows in a magnetic field

38
Q

38 What does magnetic flux density measure?

A

strength of a magnetic field

39
Q

39 What are the units for magnetic flux density?

A

tesla, or newtons/amp metre

40
Q

40 What is a transformer?

A

a device for changing the potential difference of an electricity supply

41
Q

41 What does a transformer do?

A

changes the potential difference of an electricity supply

42
Q

42 What are the two sets of coils in a transformer called?

A

primary and secondary coils

43
Q

43 What are the coils in a transformer wound onto?

A

iron core

44
Q

44 What does potential difference measure?

A

energy transferred by each coulomb of charge

45
Q

45 What is the equation for calculating electrical power?

A

power = current x potential difference

46
Q

46 What are the units for electrical power?

A

watts

47
Q

47 100 W of power are transferred to a transformer via the primary coil. How much power is transferred away from the transformer?

A

100 W

48
Q

48 What is the national grid?

A

the wires and transformers that send electricity around the country

49
Q

49 What is a transmission line?

A

the wires on pylons or underground that transfer electricity

50
Q

50 What is the difference between a step-up and a step-down transformer?

A

one increases the voltage and the other decreases it