Separate Physics - 6.7

Question 1

Where, in a magnet, is the magnetic force the strongest?

Answer 1

The poles

Question 2

What happens when two magnets are brought closer together?

Answer 2

They exert a force on one another

Question 3

What do two like poles do?

Answer 3

They repel each other

Question 4

What do two unlike poles do?

Answer 4

They attract each other

Question 5

What is attraction and repulsion between two magnetic poles an example of?

Answer 5

Non-contact force

Question 6

What does a permanent magnet produce?

Answer 6

Its own magnetic field

Question 7

What is an induced magnet?

Answer 7

A material which becomes a magnet when it is placed in a magnetic field

Question 8

What does induced magnetism cause?

Answer 8

A force of attraction

Question 9

What happens when an induced magnet is removed from the magnetic field?

Answer 9

Loses most / all of its magnetism quickly

Question 10

What is the magnetic field?

Answer 10

The region around a magnet where a force acts on another magnet or on a magnetic material

Question 11

Give some examples of a magnetic material

Answer 11

• Iron
• Steel
• Cobalt
• Nickel

Question 12

What force exists between a magnet and a magnetic material?

Answer 12

Attraction

Question 13

What does the strength of a magnetic field depend on?

Answer 13

The distance from the magnet (with the field being strongest at the poles)

Question 14

How can the direction of the magnetic field be identified?

Answer 14

It is given by the direction of the force which would act on another north pole placed at that point

Question 15

What is the direction of a magnetic field line?

Answer 15

From the north (seeking) pole to the south (seeking) pole of the magnet

Question 16

What does a magnetic compass comprise of?

Answer 16

A small bar magnet (pointing towards the Earth’s magnetic field)

Question 17

What happens when a current flows through a conducting wire?

Answer 17

A magnetic field is produced

Question 18

What affects the strength of a magnetic field through a conducting wire with current flowing through?

Answer 18

The current through the wire and the distance from the wire

Question 19

How can the strength of a magnetic field created by a current through a wire be increased?

Answer 19

The wire can be shaped, forming a solenoid (the magnetic field inside a solenoid is strong and uniform)

Question 20

What is the shape of the magnetic field around a solenoid?

Answer 20

A similar shape to that of a bar magnet

Question 21

What does an iron core in a solenoid do?

Answer 21

Increases the strength of the magnetic field

Question 22

What is an electromagnet?

Answer 22

A solenoid with an iron core (it can be turned on and off)

Question 23

Higher Q. What is the motor effect?

Answer 23

A conductor carrying a current placed in a magnetic field causes the magnet and the conductor to exert a force on one another

Question 24

Higher Q. What does Fleming’s left-hand rule represent?

Answer 24

The relative orientation of the force, current in the conductor and magnetic field

Question 25

Higher Q. What does a coil of wire, carrying a current in a magnetic field, tend to do?

Answer 25

Rotate (the basis of an electric motor)

Question 26

Higher Q. What does the force on a conductor in a magnetic field cause?

Answer 26

The rotation of the coil in an electric motor

Question 27

Separate Higher Q. How do loudspeakers and headphones use the motor effect?

Answer 27

Converting variations in current in electrical circuits to the pressure variations in sound waves

Question 28

Separate Higher Q. What is the generator effect?

Answer 28

A potential difference induced across the ends of a conductor, inducing a current

Question 29

Separate Higher Q. What can cause a potential difference to be induced across the ends of a conductor?

Answer 29

If an electrical conductor moves relative to a magnetic field or there is a change in the magnetic field around a conductor

Question 30

Separate Higher Q. An induced current generates a magnetic field: what does this oppose?

Answer 30

The original change: either the movement of the conductor or the change in magnetic field

Question 31

Separate Higher Q. In an alternator, what does the generator effect cause?

Answer 31

AC

Question 32

Separate Higher Q. In a dynamo, what does the generator effect cause?

Answer 32

DC

Question 33

Separate Higher Q. How do microphones use the generator effect?

Answer 33

They convert the pressure variations in sound waves into variations in current in electrical circuits

Question 34

Separate Higher Q. What does a basic transformer consist of?

Answer 34

A primary and secondary coil, wound on an iron core

Question 35

Separate Higher Q. If a transformer was 100% efficient, what would the electrical power output equal?

Answer 35

The electrical power output would equal the electrical power input

Question 36

Separate Higher Q. How do transformers use AC?

Answer 36

The effect of an AC in one coil induces a current in another

Question 37

Separate Higher Q. How does the ratio of the potential differences across the two coils vary?

Answer 37

The potential differences depend on the ratio of the number of turns on each