# Physics (paper 1) 📍 Flashcards

1
Q

What are the function of waves?

A

They transfer energy and information without transferring matter

2
Q

Wavelength (λ)

A

Minimum distance in which a wave repeats itself

3
Q

What is a wavelength measured in?

A

Metres

4
Q

Amplitude (A)

A

Distance between the origin and the crest/trough

5
Q

Frequency (f)

A

Number of waves that pass a point in a second

6
Q

Frequency and wavelength are

A

inversely proportional
• High frequency = short wavelengths
• Low frequency = long wavelengths

7
Q

How is the wavelength measured in both waves?

A

Transverse waves:
From one peak/crest to the next

Longitudinal waves:
From the centre of one compression to the next centre of compression

8
Q

Time period (T)

A

The time taken for a single wave to pass a point

9
Q

Wave velocity (speed)

A

The distance travelled by a wave each second

10
Q

Transverse wave

A

Waves where the particles move perpendicular to the direction of energy transfer (oscillating motion)

11
Q

Examples of transverse waves

A

• Ripples on the surface of water
• S - waves
• Electromagnetic waves (eg radio, light, x rays)

12
Q

Longitudinal wave

A

Wave where the particles vibrate parallel to the direction of energy transfer (side to side motion)

13
Q

What wave can travel through a vacuum?

A

Some transverse waves eg light

14
Q

When the points are close together in a longitudinal wave

A

Compression

15
Q

When the points are spaced apart in a longitudinal wave

A

Rarefaction

16
Q

Examples of longitudinal waves

A

• Sound waves
• P - waves
• Ultrasound
• Infrasound

17
Q

Equations for wave speed (m/s)

A

• v = x/t
(Wave speed = distance/time)

• v = f x λ
(Wave speed = frequency x wavelength)

18
Q

How do you work out wavelength? (λ)

A

Length x 2

19
Q

Seismic wave

A

Wave produced by earthquakes

20
Q

Types of wave interactions through an interface

A

• Reflection
• Refraction
• Transmission
• Absorption

21
Q

Materials interact differently with waves depending on their ______

A

wavelength

22
Q

Reflection definition

A

The bouncing back of a wave at a boundary

23
Q

Refraction definition

A

When a wave changes speed at the boundary between materials of different densities

24
Q

Transmission definition

A

When a wave passes through a substance

25
Q

Absorption definition

A

When energy is transferred from the wave to the particles of a substance

26
Q

What’s an echo?

A

Sound waves being reflected off a surface

27
Q

How do waves get reflected?
(effect)

A

• Flat surfaces are the most reflective
(The smoother the surface, the stronger the reflected wave)
• Light will reflect if the object is opaque
• Electrons absorb the light energy and re emit it as a reflected wave

28
Q

How does light get refracted?
(effect)

A

• Examples like glass and water are denser than air
• So the light waves passing from the air would slow down as the wavelength shortens
• The change in speed can cause the wave to change direction (bending towards the normal)

29
Q

Waves that can be refracted

A

• Sound
• Water
• Seismic
• Electromagnetic (light, radio-waves, x-rays)

30
Q

Effects of transmission

A

• When passing through a material, waves are usually partially absorbed
• Therefore the transmitted wave may have a lower amplitude
• Eg sound waves are quieter after passing through a wall

31
Q

What does it mean if an object appears yellow?

A

• Only yellow light has been reflected
• All other frequencies of visible light have been absorbed

32
Q

What happens when waves speed up?

A

• The frequency stays the same
• The wavelength increases (gets longer)
• The waves travel away from the normal

33
Q

What happens when waves slow down?

A

• The frequency stays the same
• The wavelength decreases
• The waves travel toward the normal

34
Q

What is a normal

A

A line drawn perpendicular to an interface

35
Q

Sound waves definition

A

The vibrations of molecules

36
Q

Regions of higher and lower density in a longitudinal wave

A

Higher density: Compression
Lower density: Rarefaction

37
Q

Range of frequencies humans can hear

A

20 Hz to 20,000 Hz

38
Q

Ultrasound

A

Sound waves with a frequency above the human hearing range of 20000 Hz

39
Q

Infrasound

A

Sound waves with a frequency below the human hearing range of 20 Hz

40
Q

Explain the way the human ear works

A

• Vibrations in the air travels down the auditory canal causing the eardrum to vibrate
• Vibrations are passed onto the three small bones
• These bones amplify vibrations and transmit them to the liquid in the cochlea
• Tiny hairs in the cochlea detect vibrations and create electrical impulses
• They travel along neurones in the auditory nerve to the brain

41
Q

Incident angle

A

Angle of the entering ray

42
Q

What is the angle of reflection?

A

The angle of the exiting ray

43
Q

Angle of reflection is equal to

A

Angle of incidence

44
Q

Can sound waves travel through a vacuum? Explain.

A

• No. Longitudinal waves rely on vibrating particles to travel
• In a vacuum there are no particles that can vibrate, and so sound waves can’t be transmitted.

45
Q

How is ultrasound used in sonar?

A

• Ultrasound is emitted from a boat and travels towards the sea bed
• Ultrasound reflects off the sea bed and is detected by the boat
• The time between emission and detection is recorded
• This can be used to find out the depth of seabed

46
Q

Ultrasound uses

A

• Foetal scanning
• Sonar
• echo location

47
Q

Infrasound uses

A

• Exploration of the Earth’s core
• Detecting seismic activity

48
Q

How is ultrasound used for foetal scanning?

A

• A transducer produces and detects a beam of ultrasound waves in body
• Ultrasound waves are bounced back to the transducer by different boundaries
• The echo reaches the transducer causing it to generate electrical signals to send to the scanner
• The detector calculates the tissue’s distance from transducer using speed and time
• Time measurements are used to build up an image

49
Q

How does ultrasound operate?

A

Some of the ultrasound waves is reflected each time it passes through a boundary between two materials

50
Q

Why is ultrasound a safe method for foetal scanning compared to eg X rays?

A

• x rays are ionising whereas ultrasound isn’t
• Therefore x rays could damage tissue and mutate cells

51
Q

What is applied during foetal scanning and why?

A

Gel is applied to ensure ultrasound is absorbed not reflected off your body

52
Q

How is infrasound used in the exploration of the earths core?

A

• Earthquakes produce P-waves and S-waves
• These pass through the Earth’s centre and can be detected using seismometers
• The location and magnitude can be identified after carefully timing the arrival of its waves

53
Q

Characteristics of P-waves

A

Primary waves

• Longitudinal waves

• Faster than S-waves so are felt first during an earthquake

• Produce a forward and back motion

• Can only pass through solids and liquids

• Are very low frequency sound waves (infrasound)

54
Q

Characteristics of S-waves

A

Secondary waves

• Transverse waves

• Slower than P-waves so are felt after them during an earthquake

• Produces a side to side motion

• Can only travel through solids

• Unable to travel through the Earth’s molten outer core

55
Q

Method to calculate wave speed by measuring the frequency

A

• Measure the frequency by counting the number of waves that pass a ping on the harbour each second

• Measure the wavelength by counting the number of waves between two point on the harbour and dividing the distance by the number of waves

56
Q

[][Topic5][]
Concave meaning

A

Curving inwards

57
Q

Convex meaning

A

Curving outwards

58
Q

Focal length

A

The distance between the centre of the lens and the focal point

59
Q

Real image

A

An image that is formed where the rays of light are focused

60
Q

Virtual image

A

An image where rays of light appear to come but don’t in reality

61
Q

Incident ray

A

Light ray moving towards a boundary

62
Q

Law of reflection

A

Angle of incidence is equal to the angle of reflection

63
Q

Why might the angle of reflection have a range of values when being measured in a practical?

A

The light beam may have been wide

64
Q

Properties of red light in terms of waves

A

• Has the longest wavelength
• Has the lowest frequency

65
Q

Properties of violet light in terms of waves

A

• Has the shortest wavelength
• Has the highest frequency

66
Q

White light is

A

a combination of all the colours

67
Q

Black is

A

the absence of light

68
Q

What colour would a blue object appear through a green filter and why?

A

• Black
• Blue light is being absorbed so no light is being reflected making it appear black

69
Q

What is the critical angle?

A

The angle of incidence that gives us an angle of reflection of 90°

70
Q

What is Total Internal Reflection?

A

• When all the light is reflected back into the denser medium
• No refraction occurs

71
Q

Criteria for Total Internal Reflection to occur

A

• The rays of light must travel from a more dense to less dense medium

• The angle of incidence must be greater than the critical angle

72
Q

If the angle of incidence is less than the critical angle…

A

The light ray is refracted away from the normal

73
Q

If the angle of incidence is equal to the critical angle…

A

The light ray is refracted at 90° to the normal, along the surface of the denser medium

74
Q

Converging lens is another name for

A

Convex lens

75
Q

What do convex lens do to light?

A

They refract parallel rays of light inwards into a single point (aka focal point)

76
Q

What do concave lens do to light?

A

They refract parallel rays outwards

77
Q

The shorter the focal length…

A

The more powerful the lens are

78
Q

How do you make a lens more powerful without changing the focal length?

A

Make the lens more curved

79
Q

How is an image formed?

A

When all the light rays from a point on an object come together

80
Q

Inverted images are always

A

Real

81
Q

Virtual images are always

A

Upright

82
Q

Convex lens can produce

A

Real or virtual images

83
Q

Concave lens always produce

A

Virtual images

84
Q

Magnification equation

A

Image height / Object height

85
Q

What happens when a ray of light travels perpendicular to a boundary?

A

The direction doesn’t change since it’s travelling along the normal

86
Q

What is the critical angle of glass?

A

42°

87
Q

What do all electromagnetic (EM) waves have in common?

A

• They are transverse waves
• They travel at the speed of light

88
Q

What are the 7 waves on the EM spectrum?

A

• Microwave
• Infra red
• Visible light waves
• Ultraviolet
• Gamma rays

89
Q

What EM wave has the longest wavelength?

A

90
Q

What EM wave has the highest frequency and energy?

A

Gamma rays

91
Q

How are gamma rays produced?

A

By changes in the nucleus of an atom

92
Q

What are the 3 ionising EM waves?

A

• UV rays
• X-rays
• Gamma rays

93
Q

What is the impact of ionising waves?

A

They can damage/mutate cells and therefore cause cancer

94
Q

A

• Communications
• Satellite transmissions

95
Q

A

• Communications
• Satellite transmissions

96
Q

Uses of microwaves

A

• Heating food
• Mobile phone and satellite communication

97
Q

Uses of infrared

A

• Remote control
• Night vision
• Electrical heaters
• Cooking

98
Q

Uses of visible light waves

A

• Helps us see
• Photography

99
Q

Uses of ultraviolet

A

• Fluorescent bulbs
• Getting a suntan

100
Q

Uses of x-rays

A

• Used to image luggage and broken bones

101
Q

Uses of gamma rays

A

• Sterilising medical equipment
• Treating cancer

102
Q

Danger of microwaves

A

They heat up cells

103
Q

Danger of infrared

A

It can cause skin burns

104
Q

Dangers of ultraviolet

A

• Causes damage to skin cells (leading to cancer like X-rays and gamma rays)
• Can cause blindness

105
Q

What is diffuse reflection?

A

• When light is reflected off a surface and is scattered in different directions
• Common in rough surfaces

106
Q

What is specular reflection?

A

• When light rays reflect at the same angle they hit the surface
• Common in smooth surfaces like mirrors

107
Q

Radiowaves can be created using what type of current?

A

Alternating current

108
Q

What is an oscilloscope?

A

• A device that allows us to see the frequency of the alternating current
• This helps us determine the frequency of the radio wave

109
Q

What would happen to an object if it emits more energy than it absorbs?

A

It would lose energy and cool down

110
Q

What would happen if an object emits and absorbs the same amount of energy?

A

It would stay the same temperature

111
Q

Intensity meaning

A

The power of radiation per unit area

112
Q

What type of EM waves are included in a diagram of emitted radiation?

A

• Visible light
(in order of increasing wavelength)

113
Q

What effect does temperature of an object have on intensity?

A

• As the temperature increases, the intensity of every emitted wavelength increases
• With the shorter wavelengths increasing at a higher rate

114
Q

Why does the colour of a Bunsen burner flame change as it gets hotter?

A

• The hotter the flame, the shorter the wavelength of light emitted
• Colour changes from orange to blue

115
Q

What is the emitted radiation for an object at room temperature?

A

• Infra red radiation
• Not also visible light because we can’t see the emitted radiation

116
Q

First atom model

A

• Dalton’s billiard ball model
• Tiny sphere that couldn’t be broken up

117
Q

What atom model did JJ Thompson propose?

A

• The plum pudding model
• Sphere of positive charge with negative electrons in it

118
Q

What atom model did Rutherford propose?

A

• Nuclear model
• Positively charged nucleus surrounded by a cloud of negative electrons

119
Q

What atom model did Bohr propose?

A

• The Bohr model
• Electrons orbit the nucleus at certain distances

120
Q

[] What is the equation for calculating speed?

A

• v (m/s) = x (m) / t (s)
• Average speed = total distance / time taken

121
Q

Equation for calculating acceleration

A

• a (m/s²) = /\ v (m/s) / t (s)
• change in velocity / time taken

122
Q

Equation for calculating uniform (constant) acceleration

A

• a = v² - u² / 2x
• (final speed)² - (initial speed)² / 2 x distance travelled

123
Q

When the resultant force is 0N, what does it indicate about an object?

A

The object is either moving at constant speed or is stationary