Electromagnetism Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Magnetic field lines always point from

A

north to south.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The arrow on a magnetic field line shows

A

the direction the north pole of a compass would point if you placed it there.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

A magnet placed near unmagnetised iron will

A

attract it, since iron is a magnetic material.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

A magnet placed near unmagnetised steel will

A

attract it, since steel is a magnetic material.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

A magnet placed near copper will

A

not attract or repel the copper. Copper is not a magnetic material.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Two north poles placed close together will

A

repel.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Two south poles placed close together will

A

repel.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

A north pole and a south pole placed close together will

A

attract.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The ‘motor effect,’ describes how a wire feels a force if it is in a magnetic field and

A

it is carrying a current.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The ‘motor effect,’ describes how a wire feels a force if carries a current and

A

it is in a magnetic field.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Fleming’s left hand rule can be used to solve problems involving the ‘motor effect.’ What does the thumb represent?

A

Motion; in other words, the direction of the force on the wire.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Fleming’s left hand rule can be used to solve problems involving the ‘motor effect.’ What does the first finger represent?

A

The direction of the magnetic field, pointing from north to south.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Fleming’s left hand rule can be used to solve problems involving the ‘motor effect.’ What does the second finger represent?

A

The direction of the electric current, pointing from positive to negative.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What rule can be used to solve problems involving the motor effect?

A

Fleming’s left hand rule.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

A current carrying coil of wire in a magnetic field experiences a force. (The ‘motor effect’) How could this force be increased? (4 ways)

A

Increase the current in the coil.
Add more turns to the coil.
Make each turn of the coil bigger.
Increase the magnetic field strength.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

When a wire cuts through magnetic field lines a current is induced in it. How can the induced current be increased? (2 ways)

A

Move the wire faster.

Use a stronger magnetic field.

19
Q

What rule can be used to work out the direction of magnetic field lines around a straight current-carrying wire?

A

The right hand grip rule.

20
Q

The ‘generator effect’ describes how a current is induced when

A

a conductor cuts through magnetic field lines.

21
Q

How can the magnetic field around a current carrying solenoid be increased? (4 ways)

A

Increase the current in the solenoid.
Add more turns to the solenoid.
Increase the area of each turn on the solenoid.
Add a soft iron core, turning the solenoid into an electromagnet.

22
Q

How can the magnetic field around a current carrying electromagnet be increased? (3 ways)

A

Increase the current in the electromagnet.
Add more turns to the electromagnet.
Increase the area of each turn on the electromagnet.

23
Q

What is a uniform magnetic field?

A

When the magnetic field lines are straight, parallel and equally spaced.

24
Q

How can a uniform magnetic field be produced?

A

By bringing the north and south poles of two bar magnets close together. There will be a uniform magnetic field in the gap between them.

27
Q

What is an example of a ‘hard’ magnetic material?

A

Steel.

31
Q

What is a magnetic material?

A

A material that can be magnetised, i.e. turned into a magnet.

32
Q

What does it mean if a magnetic material is described as ‘soft’?

A

The material is easily magnetised and demagnetised.

33
Q

What is an example of a ‘soft’ magnetic material?

A

Iron.

34
Q

What does it mean if a magnetic material is described as ‘hard’?

A

The material cannot be easily magnetised. Once magnetised, it is difficult to demagnetise.

35
Q

How could the magnetic field between two magnets be strengthened?

A

Move them closer together.