Magnetism + Electromagnetism

Question 1

What is a magnetic field?

Answer 1

A magnetic field is a region where other magnets or magnetic materials experience a force

Question 2

When is field strength strongest?

Answer 2

Field strength is strongest when lines are closer together

Question 3

What two factors does magnetic field strength depend on?

Answer 3

Magnetic field strength depends on the size of the current and the distance from the wire

Question 4

What is an electromagnet?

Answer 4

An electromagnet is a solenoid with an iron core, which can be turned on and off

Question 5

What is an induced magnet?

Answer 5

An induced magnet is a magnetic material that turns into a magnet when placed in a magnetic field

Question 6

Name 4 examples of induced magnets

Answer 6

4 examples of induced magnets include iron, steel, nickel and cobalt

Question 7

What is a permanent magnet?

Answer 7

A permanent magnet produces its own magnetic field

Question 8

When is the magnetic field strongest?

Answer 8

Magnetic fields are strongest at the poles

Question 9

When does magnetic field strength decrease?

Answer 9

Magnetic field strength decreases with distance from magnet

Question 10

What is the motor effect?

Answer 10

The motor effect is when a magnet and a current-carrying conductor exert a force on each other

Question 11

How do you increase the force in a motor effect?

Answer 11

Increase the force in motor effect by increasing current, increasing magnetic field strength, increasing length of conductor

Question 12

What is the process of electric motors?

Answer 12

In electric motors :

Direct current through wire > each side of coil experiences opposite forces > coil rotates

Question 13

What is the process of loudspeakers and headphones?

Answer 13

The process of loudspeakers and headphones:

alternating current through coil > coil moves back and forth > paper cone moves back and forth > sound waves created

Question 14

Compasses point in the d_____ _ _ _ _ _ _

Answer 14

Compasses point in the direction of the magnetic field it’s in - it points north when not in presence of a magnet

Question 15

What is an alternator?

Answer 15

An alternator generates an alternating current

Question 16

What is a dynamo?

Answer 16

A dynamo generates direct current

Question 17

When will peak height increase in an alternator/dynamo

Answer 17

Peak hight increases if speed of coil increases in alternators and dynamos

Question 18

What does step up transformers do?

Answer 18

Step up transformers increase voltage and decrease current which reduces wasted heat energy in cables

Question 19

What does step down transformers do?

Answer 19

Step up transformers decrease voltage and increase current for safe use in home

Question 20

What does it mean if a transformer is 100% efficient?

Answer 20

If a transformer is 100% effecient that means input power = output power

Question 21

What is the generator effect?

Answer 21

The generator effect is when a potential difference is induced in a wire which is moving relative to a magnetic field, or experiencing a change in magnetic field

Question 22

What are two ways to induce a potential difference? (generator effect)

Answer 22

You can induce a potential difference by moving the magnet or moving the wire

Question 23

How can you swap the direction of the potential difference? (generator effect)

Answer 23

You can swap the direction of the potential difference by moving the magnet/wire in the opposite direction or starting with the/both magnets the other way round

Question 24

How can you increase the size of the induced potential different? (generator effect)

Answer 24

You can increase the size of the induced potential difference by increasing the speed of the movement of increasing the magnetic field strength