Topic 7-Magnestism and electromagnetism

Question 1

What are the two poles?

Answer 1

North and south.

Question 2

What do all magnets produce?

Answer 2

A magnetic field.

Question 3

Where is the magnetic field strongest on a magnet?

Answer 3

At the poles.

Question 4

The closer magnetic field lines are …

Answer 4

The stronger the magnetic field.

Question 5

Which direction do magnetic field lines always go?

Answer 5

From north to south.

Question 6

What forces can magnets experience?

Answer 6

Attraction or repulsion.

Question 7

North and a North?

Answer 7

Repulsion.

Question 8

South and a North?

Answer 8

Attraction.

Question 9

What device shows the direction of magnetic field lines?

Answer 9

A compass.

Question 10

What are the two types of magnets?

Answer 10

Permanent and induced.

Question 11

What is a permanent magnet?

Answer 11

A magnet that can produce its own magnetic field.

Question 12

What are induced magnets?

Answer 12

Magnetic materials that turn into a magnet when they are put into a magnetic field.

Question 13

What is the force between permanent and induced magnets?

Answer 13

Attraction.

Question 14

What happens when a current flows through a wire?

Answer 14

A magnetic field is created around the wire.

Question 15

How can you increase the strength of the magnetic field that a wire produces?

Answer 15

By wrapping the wire into a coil.

Question 16

What is the coil called that you wrap around a wire to increase the magnetic field?

Answer 16

A solenoid.

Question 17

What is a solenoid with an iron core called?

Answer 17

An electromagnet.

Question 18

What can electromagnets be used for?

Answer 18

To pick stuff up with a crane.

Question 19

What is the equation for force?

Answer 19

Magnetic flux density x current x length.

Question 20

What is the generator effect?

Answer 20

The induction of a potential difference in a wire which is moving relative to a magnetic field, or experiencing a change in magnetic field.

Question 21

What does the generator effect create?

Answer 21

A potential difference in a conductor.

Question 22

If the conductor is part of a circuit what does the generator effect create?

Answer 22

A current.

Question 23

what do dynamos generate?

Answer 23

A direct current.

Question 24

What do alternators generate?

Answer 24

An alternating current.

Question 25

How do microphones work?

Answer 25

By generating a current from sound waves.

Question 26

What type of current do transformers only work with?

Answer 26

An alternating current.

Question 27

What two types of coil do transformers have?

Answer 27

Primary and secondary.

Question 28

What are the two coils joined together with in a transformer?

Answer 28

An iron core.

Question 29

What are the two types of transformers?

Answer 29

Step up transformers and step down transformers.

Question 30

What do step up transformers have to increase the potential difference?

Answer 30

More turns on the secondary coil than the primary coil.

Question 31

What do step down transformers have to decrease the potential difference?

Answer 31

More turns on the primary coil than the secondary coil.