Topic P6 - Waves

Question 1

What happens when waves travel through a medium?

Answer 1

They transfer energy (not matter)

Question 2

Frequency definition

Answer 2

Number of complete waves passing a certain point each second

Question 3

Period definition

Answer 3

Amount of time it takes for a complete wave to pass a point

Question 4

Sound moves away…

Answer 4

the air particles don’t

Question 5

Ripple on waters surface move away…

Answer 5

The water doesn’t

Question 6

What is amplitude?

Answer 6

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

Question 7

What is wavelength?

Answer 7

Length of a full cycle of a wave

Question 8

What can happen when a wave hits a boundary?

Answer 8

• It can be absorbed
• Transmitted
• Reflected

Question 9

What are transverse waves?

Answer 9

Oscillations perpendicular (at 90 degrees) to direction of energy transfer

Question 10

What are the three types of transverse waves?

Answer 10

• Ripples In water
• Electromagnetic waves e.g light
• Waves on a string

Question 11

What are longitudinal waves?

Answer 11

Oscillations parallel to direction of energy transfer.

Question 12

Examples of longitudinal waves?

Answer 12

Sound waves

Question 13

What is the WAVE EQUATION?

Answer 13

wave speed = frequency x wavelength

Question 14

What is wave speed measured in?

Answer 14

m/s

Question 15

What is frequency measured in?

Answer 15

Hertz, Hz

Question 16

What is wavelength measured in?

Answer 16

meter

Question 17

1 __ is 1 wave per second

Answer 17

1 Hz

Question 18

How do you measure the Speed of Sound?

Answer 18

1) Speaker attached to signal generator of specific frequency
2) microphones attached to oscilloscope

Waves detected at each microphone shown as separate waves.

Move one microphone until waves line up. Distance between microphones is now equal to one wavelength

Use Wave Equation to find speed

Question 19

Refraction definition

Answer 19

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

Question 20

What happens if a wave refracts and slows down?

Answer 20

• The wavelength decreases

- Bends towards normal

Question 21

What happens if wave refracts and speeds up?

Answer 21

• Wavelength increases

- Bends away from normal

Question 22

What happens to frequency in refraction?

Answer 22

It never changes

Question 23

What happens to wave fronts after refraction?

Answer 23

Wave fronts are closer together after refraction as wavelength has decreased

Question 24

What is the angle of incidence in refraction?

Answer 24

The angle between the incoming ray and the normal

Question 25

What is the angle of refraction?

Answer 25

The angle between the normal and the angle of refraction

Question 26

What is on the ELECTROMAGNETIC SPECTRUM (EM)?

Answer 26

* Radio Waves * Microwaves * Infrared * Visible Light * Ultraviolet * X-rays * Gamma Rays

Question 27

What is an EM spectrum mnemonic?

Answer 27

* Raging * Martians * Invaded * Venus * Using * X-ray * Guns

Question 28

What colour does the Electromagnetic Spectrum go from (left to right)?

Answer 28

Red -> Violet

Question 29

What happens as the Electromagnetic Spectrum increases?

Answer 29

Increasing frequency | Decreasing Wavelength

Question 30

The EM spectrum is continuous | True or False?

Answer 30

True

Question 31

What are three EM wave characteristics?

Answer 31

* Are transverse * Transfer energy from source to absorber * Travel at same speed in air or vacuum

Question 32

Can our eyes detect Infrared light?

Answer 32

No. We can only detect Visible Light.

Question 33

How are Gamma Rays created through nucleus?

Answer 33

Gamma rays created by changes in atom’s nucleus.

Question 34

How do you produce Radio Waves?

Answer 34

* Alternating Current supplied to transmitter. * Electrons oscillate, producing radio waves * Emitted radio waves transfer energy to the receiver * Radio waves absorbed, causing electrons in receiver to oscillate * Alternating current of same frequency as radio waves induced in receiver.

Question 35

What are the uses of Radio Waves?

Answer 35

* TV | * Radio

Question 36

What are the uses of Microwaves?

Answer 36

* Satellite Communications | * Cooking

Question 37

What are the uses of Infrared Radiation?

Answer 37

* Electric Heaters * Cooking (Toasters) * Infrared Cameras

Question 38

What are the uses of Visible Light?

Answer 38

• Communications through optical fibres

Question 39

What are the uses of UV waves?

Answer 39

* Energy efficient lights | * Sun tan beds

Question 40

What are the uses of X-rays and gamma rays?

Answer 40

* Medical imaging | * Medical treatments

Question 41

Radiation Dose definition

Answer 41

Measure of the risk of harm to body tissues due to exposure to radiation. It is measured in sieverts.

Question 42

What does risk of EM waves depend on?

Answer 42

Risk depends on: • Size of dose • Type of radiation

Question 43

What are the 2 types of ionising radiation?

Answer 43

* UV | * X-rays and gamma rays

Question 44

Harmful effects of UV on human body tissue?

Answer 44

* Can prematurely age skin | * Increases risk of skin cancer

Question 45

Harmful effects of X-rays and gamma rays on human body tissue?

Answer 45

* Gene mutation | * Cancer