P6: Waves Flashcards

1
Q

what are the two types of waves

A

transverse and longitudinal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

define a transverse wave

A

A wave for which the oscillations are perpendicular to the direction of wave transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is a longitudinal wave?

A

a wave for which the oscillations are parallel to the direction of energy transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Give two examples of transverse waves

A
  1. Electromagnetic waves
  2. Seismic s-waves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Give two examples of longitudinal waves

A
  1. Sound waves
  2. Seismic p-waves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the two parts of a longitudinal wave called?

A
  • compressions and rarefractions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Define amplitude

A
  • the maximum displacement of a point on a wave away from its undisturbed position.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the definition of wavelength?

A

The wavelength of a wave is the distance from a point on one wave to the equivalent point on the adjacent wave.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the definition of frequency? Give the unit

A

The frequency of a wave is the number of waves passing a point each second.
- Hertz , Hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is wave speed?

A

The wave speed is the speed at which the energy is transferred (or the wave moves) through the medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does a wave transfer?

A

energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

State the equation used to calculate wave speed. Give appropriate units.

A

Wave speed = frequency x wavelength
speed = m/s
frequency = Hz
Wavelength = m

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens to waves at the boundary between materials?

A

They can be reflected, absorbed or transmitted.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do sound waves travel through a solid?

A
  • the particles in the solid vibrate and transfer kinetic energy through the material
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the frequency range of human hearing?

A

20 Hz - 20kHz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are ultrasound waves?

A
  • waves which have a frequency higher than the upper limit of human hearing
  • (20kHz)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Give an example use for ultrasound waves

A
  • medical or industrial imaging
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What natural event causes seismic waves to be produced? What types are produced?

A
  • Earthquakes
  • They produce both P-waves and S-waves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

State a difference between the mediums that P-waves and S-waves can travel through

A
  • P waves travel through both solids and liquids
  • S-waves only travel through solids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What technique is used to detect objects in deep water and measure water depth and how?

A
  • Echo sounding
  • high frequency sound waves are emitted, reflected and detected
  • time difference between emission and detection alongside wave speed, are used to calculate distances
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What type of spectrum do electromagnetic waves form?

A

A continuous spectrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

order the types of electromagnetic radiation from lowest to highest frequency

A
  • radio waves
  • microwaves
  • infrared
  • visible light
  • ultraviolet
  • X-rays
  • Gamma rays
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How do the speeds of EM radiation differ in a vacuum and in air?

A
  • EM waves all travel at the same speed in a vacuum and in air
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What property of waves in different mediums causes refraction?

A
  • velocity
  • wave speed is slower in denser materials, causing refraction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

In which direction ( relative to the normal) do waves refract when entering a denser medium?

A
  • they bend towards the normal
  • the angle of refraction is less than the angle of incidence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What type of waves can be produced by oscillations in an electrical circuit?

A
  • Radiowaves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How can radio waves create an alternating current in a circuit?

A
  • When radio waves are absorbed , they can induce oscillations of electrons in a circuit
  • with the same frequency as the radiowaves themselves
  • causing alternating current
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Where do gamma rays originate from ?

A
  • they orginate from changes in the nuclei of atoms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

give two health effects caused by ultraviolet waves

A
  • they can cause the skin to age prematurely
  • this can increase the risk of developing skin cancer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

give two health effects caused by x-rays and gamma rays

A
  • they are ionising radiation so can cause mutations in genes
  • they can lead to increased risk of developing various cancers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Give three practical uses for infrared radiation

A
  1. electrical heaters
  2. cooking food
  3. infrared cameras
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Give two practical uses for microwave radiation

A
  1. Satellite communications
  2. Cooking food
33
Q

Give two practical uses for radio waves

A
  1. television transmission
  2. radio transmission
34
Q

What wave phenomenon is used by lenses to form an image

A

refraction

35
Q

How does a convex lens form an image ?

A
  • Parallel rays of light are refracted and brought together at a point known as the principal focus
36
Q

What is meant by the focal length of a lens?

A
  • the distance from the lens to the principal focus
37
Q

What is the difference between the image produced by a convex and a concave lens?

A
  • convex lenses can produce real or virtual images
  • concave lenses can only produce virtual images
38
Q

Why does magnification not have a unit

A
  • it is the ratio between image height and object height
  • ratios do not require units
39
Q

what symbol is used to represent a convex lens in a ray diagram?

A

40
Q

what symbol is used to represent a concave lens in a ray diagram?

A

🞃
|
🞁

41
Q

what determines the colour of visible light waves?

A

the wavelength and frequency of the light waves

42
Q

What colour of visible light has the highest frequency? What colour of visible light has the largest wavelength?

A
  • blue
  • red
43
Q

What is a specular reflection?

A
  • Reflection that happens when parallel waves are reflected in a single direction by a smooth surface
  • produces an image
44
Q

What is a diffuse reflection?

A
  • Reflection that happens when parallel waves are reflected by a rough surface and the reflected rays are scattered in lots of different directions
  • this does not produce an image
45
Q

How does a red colour filter work?

A
  • a red filter absorbs all wavelength of light other than those in the red range of the spectrum
  • this means only red light passes through the filter
46
Q

What determines the colour of an opaque object?

A
  • different objects reflect different wavelengths of light by different amount
  • the wavelengths that are most strongly reflected determine the colour
47
Q

What happens to the wavelengths of light that aren’t reflected by an opaque object?

A
  • any wavelengths that aren’t reflected are absorbed by the object
48
Q

What colour does an object appear if all wavelengths are reflected by equal amounts>

A

white

49
Q

What colour does an object appear if all wavelengths are absorbed?

A
  • black
50
Q

what is radiation dose?

A

Radiation dose is a measure of the risk of harm resulting from an
exposure of the body to the radiation

51
Q

Why do bananas appear yellow?

A

Bananas absorb all wavelengths of light
except the yellow part of the visible
spectrum which is reflected

52
Q

Explain why a piece of paper
appears white (2)

A
  • All of the wavelengths of visible light are reflected from its surface.
  • They combine together and produce white light
53
Q

What happens if you view a blue
object with a blue filter?

A

● Blue light is reflected by blue object
● Blue filter transmits blue light and
absorbs all other wavelengths
So object looks blue

54
Q

. What happens if you view a red
object with a blue filter?

A

● Red light is reflected by red object
● Blue filter will absorb red light
● So object appears black

55
Q

What are transparent objects?

A

● Objects that transmit light
● In straight lines

56
Q

What are translucent objects?

A

● Objects that transmit light
● But can also scatter it so you cannot see
clearly through them

57
Q

What provides evidence that
the S-waves do not travel
through the outer core?

A

The S wave shadow zone

58
Q

What does the S wave shadow zone tell us about the outer core?

A

The outer core is liquid as S waves cannot travel through liquids

59
Q

Why do both waves change
direction as they go deeper into
the Earth?

A

The density of the Earth changes – this causes
the waves to change speed and refract

60
Q

what do all bodies (objects) emit and absorb?

A

infrared radiation

61
Q

what hat happens to the quantity of infrared radiation emitted by an object as temperature increases?

A

the hotter the object, the more infrared radiation it will emit

62
Q

What is a perfect black body?

A

An object that absorbs all of the radiation that is incident upon it

63
Q

How much radiation does a perfect black body reflect or transmit?

A

None.

64
Q

Why is a perfect black body the best possible emitter of radiation?

A
  • it is a perfect absorber since it absorbs all radiation incident upon it
  • a perfect absorber is also a perfect emitter
65
Q

What can be said about the rates of emission and absorption for a body at constant temperature?

A

The body is absorbing and emitting radiation at the same rate

66
Q

what can be said about the rates of emission and absorption for a body increasing in temperature?

A

the body is absorbing radiation faster than it is emitting it

67
Q

Give two factors that affect the temperature of the Earth?

A
  1. The Earth’s rate of absorption and emission of radiation
  2. the amount of reflection of radiation into space
68
Q

Explain why a mug of hot
chocolate will get cold after 1
hour

A

● The hot chocolate is initially hotter than
the surroundings
● Therefore it will emit more infrared
radiation than it absorbs
● So its temperature decreases

69
Q
  1. Explain why the surface
    temperature of the Earth increases during the day
A

● During the day the sun is shining
● More infrared radiation will be absorbed
by the surface of the Earth than emitted

70
Q

. Explain why the surface
temperature of the Earth
decreases during the nigh

A

● During the night, there is less infrared
radiation absorbed by the surface of the
Earth than emitted

71
Q

.What type of surfaces are best and worst
at absorbing and emitting
infrared radiation?

A

best : Black matt surfaces
worst: white shiny surfaces

72
Q

Why are light, shiny blankets
used to keep people warm?

A

● A light shiny outer surface emits a lot
less radiation than dark/matt surfaces
● The person will be kept warm as the
infrared radiation emitted is reduced

73
Q

what is the exception to the refraction rule

A
  • if waves enter or leave the medium along the normal ( at right angles to the surface)
  • they do not change direction
74
Q

what happens when electromagnetic waves are absorbed !

A
  • it causes changes to atoms eg causing electrons to change energy levels
  • these changes can result in EM waves being generated and absorbed over a wide frequency range
75
Q

Describe the image shown when an object is more than 2 focal lengths from the convex lens

A
  • diminished
  • inverted
  • real
76
Q

describe the image shown when an object is between 1 and 2 focal lengths from the convex lens

A
  • magnified
  • Inverted
  • Real
77
Q

describe the image shown when an object is less than one focal length between the convex lens

A
  • magnified
  • upright
  • virtual
78
Q

Describe the image shown from an object with a a concave lens

A
  • diminished
  • upright
  • virtual
79
Q

What is white light and what happens when it is passed through a prism

A
  • a mixture of all the different colours
  • it splits into a spectrum : red orange yellow green blue indigo violet