Topic 4 & 5 Waves, light and the EM Spectrum Flashcards
1 Name three different types of wave.
any three from: light, sound, waves on water, seismic waves
2 What property of a wave does the wavelength describe?
the distance from one wave to the same place on the next wave
3 What are the units for wavelength?
metres
4 What property of a wave does the frequency describe?
the number of waves per second
5 What are the units for frequency?
hertz
6 What is transferred by a wave?
energy but no matter
7 What does amplitude mean?
the height of a wave, more correctly, the maximum displacement of a particle from its rest position
8 In which direction do the particles in a sound wave move compared to the direction the wave is travelling?
backwards and forwards in the same direction as the wave
9 What word is used to describe waves like sound waves?
longitudinal
10 What word is used to describe waves like the waves on water?
transverse
11 Name a type of transverse wave.
waves on water, some seismic waves, light waves
12 Name a type of longitudinal wave.
sound, some seismic waves
13 What is the difference between longitudinal and transverse waves?
the direction the particles move compared to the direction the wave is travelling
14 What word describes the number of waves per second?
frequency
15 What word describes the time taken for one wave to pass?
period
16 What word describes the distance between a point on one wave and the same point on the next wave?
wavelength
17 What are the units for frequency?
hertz
18 Name two things that waves can transfer.
energy and information
19 Name one thing that waves do not transfer.
matter
20 What is the equation that links wave speed, frequency and wavelength?
wave speed=frequency x wavelength
21 What two things do you need to measure to find the speed of a wave?
either the time to cover a certain distance, or the wavelength and the frequency
22 Describe the path of light when you watch TV.
TV to eye
23 Describe the path of light when you sit underneath a lamp and read a book.
lamp to book to eye
24 What is the word that describes light bouncing off a material?
reflection
25 What does refraction mean?
changing the direction of a wave
26 When does refraction happen to light waves?
when light goes into or out of a material
27 Name three materials that light can travel through.
any three transparent materials, such as air, glass, water, Perspex
28 Why is it difficult to see the exact positions of objects on the bottom of a swimming pool?
light is refracted as it leaves the water
29 What does the frequency of a wave describe?
number of waves per second
30 What are the units for frequency?
hertz
31 What does the wavelength of a wave describe?
distance from one point on a wave to the same point on next wave
32 What are the standard units for wavelength?
metres
33 What does refraction mean?
waves changing direction when they go from one material to another
34 What is a vacuum?
empty space
35 What materials can light pass through?
vacuum, air, glass, water
36 Are light waves transverse or longitudinal?
transverse
37 What do all waves transfer?
energy
38 A nanometre is one millionth of a millimetre. Why are nanometres sometimes used for giving the wavelengths of light waves?
the wavelength is very short
39 What are the colours of the rainbow?
red, orange, yellow, green, blue, indigo, violet
40 What piece of apparatus can you use to split up light to form a spectrum?
prism
41 Which colour in visible light has the longest wavelength?
red
42 What does EM stand for?
electromagnetic
43 Are EM waves transverse or longitudinal?
transverse
44 Which part of our bodies detects visible light?
eyes
45 Which part of our bodies detects infrared?
skin
46 H Name two parts of the EM spectrum that can travel through the atmosphere.
All can to some extent, but the expected answer at this stage is infrared and visible light, as we can detect both of these from the Sun .
47 Which electromagnetic waves have the highest frequency?
gamma rays
48 Which electromagnetic waves have the longest wavelengths?
radio waves
49 Which electromagnetic waves have lower frequencies than visible light?
infrared, microwaves, radio waves
50 Which electromagnetic waves have higher frequencies than visible light?
ultraviolet, X-rays, gamma rays
51 Which colour of visible light has the shortest wavelength?
violet
52 Which colour of visible light has the highest frequency?
violet
53 Which colour of visible light has the lowest frequency?
red
54 Which part or parts of the electromagnetic spectrum is used for cooking?
infrared, microwaves, radio waves
55 Which part or parts of the electromagnetic spectrum is used for sending TV programmes?
radio waves, microwaves
56 Which part of the electromagnetic spectrum is used in TV remote controls?
infrared
57 Which part of the electromagnetic spectrum is detected by our eyes?
visible
58 Which part of the electromagnetic spectrum is emitted by toasters and grills?
infrared
59 Which part of the electromagnetic spectrum is used for mobile phone communications?
microwaves
60 Which part of the electromagnetic spectrum are light bulbs designed to emit?
visible light
61 Which part of the electromagnetic spectrum is used to cook food from the inside?
microwaves
62 Which part of the electromagnetic spectrum is used to treat cancer?
gamma rays
63 Which part of the electromagnetic spectrum can be used to look inside bodies?
X-rays
64 H How are radio waves produced?
by oscillations in electrical circuits
65 H How are radio waves detected?
They produce oscillations in circuits attached to an aerial.
66 H Why do radio waves sometimes have a longer range than microwaves?
refraction in the atmosphere
67 Which transfers the most energy: red, green or violet light?
violet
68 Which part of the electromagnetic spectrum is used to sterilise surgical instruments?
gamma rays
69 Which part of the electromagnetic spectrum is used to examine luggage in airports?
X-rays
70 Which part of the electromagnetic spectrum is used to sterilise water?
ultraviolet
71 Which part of the electromagnetic spectrum do fluorescent materials emit?
visible light
72 Which part of the electromagnetic spectrum is produced inside many low energy light bulbs?
ultraviolet
73 Which part of the electromagnetic spectrum is emitted by radioactive materials?
gamma rays
74 Which part of the electromagnetic spectrum is used to make images of bones?
X-rays
75 Which part of the electromagnetic spectrum can cause skin cancer?
ultraviolet
76 Which part of the electromagnetic spectrum can cook things by heating water inside them?
microwaves
77 What way do transverse waves move in the direction of travel?
Right angles to the direction of travel.
78 What way do longitudinal waves move in the direction of travel?
Parallel to the direction of travel.
79 what is the frequency of a time period of 0.08s?
Time period = 1/frequency
So… 1/0.08s = 12.5Hz
What types of waves are refracted?
All types of waves.
What happens to a water wave when it travels from a shallow water into deep water?
The wave direction bends away from the normal because it speeds up.
When a wave passes into a slower medium, what happens to its wavelength?
Reduces.
Waves slow down so the waves catch up with other, bending towards the normal.
83 What length of wavelengths travel better through glass?
Shorter wavelengths like ultraviolet pass better through glass than longer wavelengths like infrared.
What can detect objects underwater?
Echo sounding
Below 20Hz hearing range is know as?
Infrasound.
Above 20,000Hz hearing range is known as?
Ultrasound
Which waves can travel through the earth’s core, P or S waves?
P-waves are able to travel through the Earth’s core.
They can travel through liquids and solids.
Longitudinal waves.
Which way does the light bend going from air to glass to water?
Light refracts towards the normal.
Which way does the light bend going from water or glass to air?
Light refracts away from the normal.
What 4 ways does a wave do when reaching an interface between two different materials?
Reflected - the wave “bounces” off.
Refracted - the waves passes through the material but at a different direction.
Transmitted - pass through, not absorbed or reflected.
Absorbed - wave disappears as the energy it is carrying is transferred to the material.
How does the human ears detect sound?
How does the cochlea work?
What is sonar equipment used for?
Carried on ships or submarines uses a similar method to find the depth of the sea or to detect fish.
How do ultrasound scans work?
What can longitudinal waves travel through?
Solids
Liquid
And gases
What can transverse waves travel through?
Only transmitted by solids
P waves are…
Longitudinal
S-waves are…
Transverse
What is the shadow zone of mainly S-waves but also P-waves?
The area where the waves can’t reach.
Bigger on S-waves than P-waves.
Which term is used to refer to regular reflection from a smooth surface in a single direction?
Specular reflection
Which term is used to refer to the scattering of light by a rough surface?
Diffuse reflection
What type of images do convex lenses form?
Convex lenses form both real and virtual images. Both convex and concave lenses can form virtual images.
What is the critical angle?
The critical angle is minimum angle at which total internal reflection takes place. For glass to air it is about 42°.
What is a translucent material?
A translucent material transmits light, but no clear shapes can be seen.
A light ray passes from air into water at an angle of 30°. Which of these angles is likely to be the angle of refraction?
The angle of refraction is 22°. The light ray slows down and bends towards the normal line.
What happens to a light ray when it travels from water into air?
The light ray bends away from the normal because it passes into a less dense material and speeds up.
What types of images do concave lenses form?
Concave lenses form only virtual images. Convex lenses form both real and virtual images.
What name is given to the distance between the lens and the principal focus?
Focal length is the distance between the lens and the principal focus.
Where should the object be placed to use a convex lens as a magnifying glass?
Closer than the focal length will produce an upright, magnified image with a convex lens. From F to 2F the image is inverted.
What is the unit for the power of a lens?
The power of a lens is measured in dioptres (D).
What is the focal length of a 6.67 D lens?
15 cm. The focal length is the reciprocal of the power, so f = 1 / 6.67 = 0.15 m = 15 cm.
Which electromagnetic wave is used in satellite communication?
Microwaves are used in satellite communication. Radio waves are refracted by the ionosphere.
Which EM wave has the longest wavelength?
Microwaves have a longer wavelength than X-rays and gamma rays. Gamma rays have the shortest wavelengths overall.
What is the total internal reflection?
If the angle of incidence increases further, the light is completely reflected inside the glass.
This is called total internal reflection and the angle of incidence at which this starts to happen is called the critical angle.
A diagram showing how a converging (convex) lens forms a real image.
A ray diagram showing a converging lens being used as a magnifying glass.
The electromagnetic spectrum and its uses and wavelengths.
What is a phrase to remember the order of the visible light?
ROY G BIV
What material is only visible when UV light shines on them?
Fluorescent materials.
