1) Waves

Question 1

Define transverse waves

Answer 1

Particles vibrate perpendicularly to the direction of energy transfer

Question 2

Define longitudinal waves

Answer 2

Particles vibrate parallel to the direction of energy transfer

Question 3

What is the wavelength?

Answer 3

distance between two peaks

Question 4

What is the amplitude?

Answer 4

distance from peak to the middle

Question 5

What is the symbol for wavelength?

Answer 5

Greek letter pronounced lambda [ λ ]

Question 6

What is frequency measured in?

Answer 6

Hertz (Hz)

Question 7

What does a frequency of 1 Hz mean?

Answer 7

1 wave per second

Question 8

What is the time period of a wave?

Answer 8

The time taken to produce one wave

Question 9

What is the equation linking time period (T) and frequency (f)?

Answer 9

T = 1/f

Question 10

What is the equation relating wave speed (v), frequency (Hz) and wavelength (lambda)?

Answer 10

“wave speed = frequency bywavelength”

Question 11

What is wavespeed measured in?

Answer 11

m/s

Question 12

What is wavelength measured in?

Answer 12

metres

Question 13

What are the uses of radio waves?

Answer 13

• broadcasting

- communications

Question 14

What are the uses of microwaves?

Answer 14

• cooking

- satellite transmissions

Question 15

What are the uses of infrared?

Answer 15

• heaters

- night vision equipment

Question 16

What are the uses of visible light?

Answer 16

• optical fibres

- photography

Question 17

What are the uses of ultraviolet?

Answer 17

• fluorescent lamps

Question 18

What are the uses of x-rays?

Answer 18

• observing the internal structures of objects and materials, including for medical applications

Question 19

What are the uses of gamma rays?

Answer 19

• sterilising food

- medical equipment

Question 20

What type of waves has the longest wavelength and lowest frequency?

Answer 20

Radio waves

Question 21

What type of waves have the shortest wavelength and highest frequency?

Answer 21

Gamma rays

Question 22

List the 7 types of radiation in the electromagnetic spectrum in order of lowest frequecy and longest wavelength to highest frequency and shortest wavelength

Answer 22

• radio waves
• microwaves
• infra-red
• visible light
• ultra violet
• X-rays
• gamme rays

Question 23

What effects on the body do microwaves have?

Answer 23

• internal heating of body tissue

Question 24

What effects on the body does infrared have?

Answer 24

• skin burns

Question 25

What effects on the body do radiowaves have?

Answer 25

- none

Question 26

What effects on the body does visible light have?

Answer 26

- blindness

Question 27

What effects on the body does ultra violet have?

Answer 27

- damage to surface cells - cancer - blindness

Question 28

What effects on the body do gamma rays have?

Answer 28

- cancer | - DNA mutations

Question 29

Define Doppler effect

Answer 29

"The change in wave frequency during the relative motion between a wave source and its observer"

Question 30

How long are the wavelengths when the sound is travelling towards the observer?

Answer 30

- short - high frequency - high pitched sound

Question 31

How long are the wavelengths when the sound is travelling away from the observer?

Answer 31

- longer wavelength - lower frequency - lower pitch

Question 32

Define incident ray

Answer 32

The ray of light that is going towards the normal

Question 33

Define reflection ray

Answer 33

The ray that is going away from the normal

Question 34

What is the law of reflection?

Answer 34

- That i=r | - angle of incidence = angle of reflection

Question 35

What degree is the normal to the mirror/glass block?

Answer 35

90° or perpendicular

Question 36

Define critical angle

Answer 36

The angle where light will be refracted along the surface of the material

Question 37

What is the critical angle of glass?

Answer 37

42°

Question 38

Define total internal reflection

Answer 38

When the angle of incidence is greater that the critical angle, all the light is reflected

Question 39

What happens in an optical fibre?

Answer 39

The light travels down the fibre by repeated total internal reflection

Question 40

Define refraction

Answer 40

Refraction is the change in direction of light as it enters either a more or less dense medium and either slows down or accelerates. 

Question 41

What is the name given to a medium which light travels slower?

Answer 41

Optically dense

Question 42

What happens when light enters a more optically dense material?

Answer 42

The light refracts towards the normal

Question 43

What happens when light enters a less optically dense material?

Answer 43

The light refracts away from the normal

Question 44

Define refractive index (n)

Answer 44

The ratio of the speed of light in a material to the speed of light in a differently dense material

Question 45

How do you find the refractive index?

Answer 45

n = sin i (angle of incidence)/ sin r (angle of refraction)

Question 46

Rearrange the refractive index equation to find i (angle of incidence)

Answer 46

i = sin-1(n sin r)

Question 47

Rearrange the refractive index equation to find r (angle of refraction)

Answer 47

r = sin-1(sin i/n)

Question 48

What is the equation linking critical angle (c) and the refractive index (n)?

Answer 48

sin c = 1/n

Question 49

Can sound travel through a vacuum?

Answer 49

no

Question 50

Are sound waves transverse or longitudinal waves?

Answer 50

Longitudinal