P6 - Waves

Question 1

What is the definition of frequency?

Answer 1

Number of complete waves passing a certain point each second.

Question 2

What is the period?

Answer 2

The amount of times it takes for a complete wave to pass a point.

Question 3

What is the amplitude?

Answer 3

Maximum displacement of a point on a wave from its rest position.

Question 4

What is the wavelength?

Answer 4

The length of a full cycle of a wave

Question 5

What is a transverse wave?

Answer 5

Oscillations perpendicular to direction of energy transfer.

Question 6

What are 3 examples of a transverse wave?

Answer 6

1. Ripples in water
2. Electromagnetic waves (eg. Light)
3. Waves on a string

Question 7

What is a longitudinal wave?

Answer 7

Oscillations parallel to direction of energy transfer.

Question 8

What are 2 examples of longitudinal waves?

Answer 8

1. Sound waves
2. P - waves

Question 9

What is refraction?

Answer 9

When a wave changes direction as it crosses a boundary between two materials at angle to the normal.

Question 10

What 3 things are EM waves?

Answer 10

1. Transverse
2. Transfer energy from source to absorber
3. Travel at some speed in air or vacuum.

Question 11

What are the EM waves in order?

Answer 11

Radio waves
Microwaves
Infrared
Visible light
Ultra violet
X - Rays
Gamma Rays

Question 12

What are radio waves used for?

Answer 12

TV
Radio

Question 13

What are microwaves used for?

Answer 13

Satellite communications
Cooking

Question 14

What are infrared waves used for?

Answer 14

Electric heaters
Cooking
Infrared cameras

Question 15

What are visible light used for?

Answer 15

Communications through optical fibres

Question 16

What is UV used for?

Answer 16

Energy sufficient lights
Sun tan beds

Question 17

What are X - Rays and gamma rays used for?

Answer 17

Medical imaging
Medical treatments

Question 18

How can UV be dangerous?

Answer 18

Can prematurely age skin
Increases risk of skin cancer

Question 19

How can X - Rays and gamma rays be dangerous?

Answer 19

Gene mutation
Cancer

Question 20

How can X - Rays and gamma rays be dangerous?

Answer 20

Gene mutation
Cancer

Question 21

What does the earth do in daytime?

Answer 21

Absorbs more radiation than it emits

Question 22

What does the earth do in nighttime?

Answer 22

Earth emits more radiation than it absorbs.

Question 23

What does the earth do in nighttime?

Answer 23

Earth emits more radiation than it absorbs.

Question 24

How does sound travel through air?

Answer 24

As a series of compressions and rare fractions

Question 25

What does the sound hitting a solid cause to happen?

Answer 25

Particles in the solid to vibrate Particles hit next particles in line and so on

Question 26

How do sound waves travel through a solid?

Answer 26

As series of vibrations

Question 27

What happens when a compass isn’t near a magnet?

Answer 27

It’s needle points north to line up with the earths magnetic field.

Question 28

What are two factors that the magnetic field strength depends on?

Answer 28

Size of current Distance from the wire

Question 29

What does twisting a wire into a solenoid do?

Answer 29

Increases the magnetic field strength around the wire

Question 30

What is an electromagnet?

Answer 30

A solenoid with an iron core. It is a magnet that can be turned on and off.

Question 31

What are 3 ways to increase force?

Answer 31

Increase the current Increase the magnetic field strength Increase the length of the conductor

Question 32

What are three ways to increase the force?

Answer 32

Increase the current Increase the magnetic field strength Increase the length of the conductor

Question 33

What are electric motors?

Answer 33

Direct current is passed through wire Each side of the coil experiences opposite forces Coil rotates

Question 34

What are alternators?

Answer 34

Generate alternating current

Question 35

What are dynamos?

Answer 35

Generate direct current

Question 36

What is a step up transformer?

Answer 36

Increase the voltage from the primary coil to the secondary coil

Question 37

What is a step down transformer?

Answer 37

Decreases voltage from primary coil to the secondary coil.

Question 38

What is a permanent magnet?

Answer 38

Produces its own magnetic field

Question 39

Where is magnetic field strongest?

Answer 39

At the poles

Question 40

When does the magnetic field strength decrease?

Answer 40

With distance from magnet

Question 41

What do field lines show?

Answer 41

Direction force would act on a North Pole, if placed at the point.

Question 42

What are the four magnetic materials?

Answer 42

Iron Steel Nickel Cobalt