1
Q
What is a transverse wave?
A
A wave where the oscillations are perpendicular to the direction of wave travel.
2
Q
What is a longitudinal wave?
A
A wave where the oscillations are parallel to the direction of wave travel.
3
Q
Give an example of a transverse wave.
A
Light waves.
4
Q
Give an example of a longitudinal wave.
A
Sound waves.
5
Q
What are compressions and rarefactions?
A
Compressions are areas where particles are close together; rarefactions are where particles are spread apart.
6
Q
What is amplitude?
A
The maximum displacement from the equilibrium position.
7
Q
What is a wavefront?
A
A line connecting points in a wave that are at the same phase of oscillation.
8
Q
What is frequency?
A
The number of waves that pass a point per second, measured in hertz (Hz).
9
Q
What is wavelength?
A
The distance between the same point on two consecutive waves, e.g. crest to crest.
10
Q
What is the period of a wave?
A
The time it takes for one full wave to pass a fixed point.
11
Q
Do waves transfer matter?
A
No, they transfer energy and information without transferring matter.
12
Q
How do particles behave in wave motion?
A
They oscillate around a fixed position, not moving along with the wave.
13
Q
What is the formula for wave speed?
A
Wave speed = Frequency × Wavelength (v = f × λ).
14
Q
What are the units of wave speed, frequency, and wavelength?
A
Speed: m/s, Frequency: Hz, Wavelength: m.
15
Q
How do you calculate frequency from time period?
A
f = 1 / T.
16
Q
If a wave has a time period of 0.01 s, what is its frequency?
A
f = 1 / 0.01 = 100 Hz.
17
Q
What is the time period of a wave with a frequency of 50 Hz?
A
T = 1 / 50 = 0.02 s.
18
Q
What happens to wave speed if frequency increases but wavelength remains constant?
A
Speed increases.
19
Q
What happens to wave speed if wavelength increases and frequency remains the same?
A
Speed increases.
20
Q
How can wave equations be used for sound and light?
A
To calculate properties like speed, frequency, or wavelength depending on what is given.
21
Q
What is the Doppler Effect?
A
A change in observed frequency and wavelength due to motion between the source and observer.
22
Q
What happens to wavefronts when the source moves towards an observer?
A
They bunch up, causing higher frequency and shorter wavelength.
23
Q
What happens to wavefronts when the source moves away from an observer?
A
They spread out, causing lower frequency and longer wavelength.
24
Q
What everyday example demonstrates the Doppler Effect?
A
An ambulance siren sounding higher when approaching and lower when moving away.
25
Can all waves be reflected?
Yes, all types of waves can reflect off surfaces.
26
What is the law of reflection?
The angle of incidence equals the angle of reflection.
27
Do frequency, speed, or wavelength change during reflection?
No, they remain the same.
28
Can all waves be refracted?
Yes, all waves can change direction when entering a different medium.
29
What happens when a wave enters a denser medium?
Its speed decreases and it bends towards the normal.
30
What happens when a wave enters a less dense medium?
Its speed increases and it bends away from the normal.
31
Does frequency change during refraction?
No, only speed and wavelength change.
32
Why does wavelength change during refraction?
Because speed changes while frequency remains constant.
33
What type of wave is light?
A transverse wave and part of the electromagnetic spectrum.
34
What are the main groups of the electromagnetic spectrum?
Radio, microwave, infrared, visible, ultraviolet, X-ray, gamma ray.
35
Do all electromagnetic waves travel at the same speed in free space?
Yes, they all travel at approximately 3 × 108 m/s in a vacuum.
36
What is the order of the electromagnetic spectrum from longest to shortest wavelength?
Radio, microwave, infrared, visible, ultraviolet, X-ray, gamma ray.
37
What is the order of the electromagnetic spectrum from lowest to highest frequency?
Radio, microwave, infrared, visible, ultraviolet, X-ray, gamma ray.
38
What is the order of colours in the visible spectrum?
Red, orange, yellow, green, blue, indigo, violet (ROYGBIV).
39
What are radio waves used for?
Broadcasting and communication, such as TV and radio signals.
40
What are microwaves used for?
Satellite transmissions and cooking.
41
Why can microwaves penetrate food and the ionosphere?
They have higher frequency and shorter wavelength than radio waves.
42
What is infrared radiation used for?
Heaters and night vision equipment.
43
What is visible light used for?
Optical fibres and photography.
44
What is ultraviolet light used for?
Fluorescent lamps and sterilisation.
45
What are X-rays used for?
Medical imaging and examining internal structures.
46
What are gamma rays used for?
Sterilising food and medical equipment due to high energy.
47
What harm can excessive microwaves cause?
Internal heating of body tissues.
48
What is a risk of too much infrared exposure?
Skin burns.
49
What damage can ultraviolet light cause?
Blindness and damage to surface skin cells, increasing cancer risk.
50
What is a hazard of exposure to gamma rays?
They can cause mutations and lead to cancer.
51
How can microwave radiation risks be reduced?
Using shielding in appliances and limiting exposure.
52
How can infrared radiation risks be minimised?
Avoid prolonged direct exposure and use protective clothing or barriers.
53
What protection helps against UV light?
Wearing sunglasses and applying sun cream.
54
What are X-rays and gamma rays classified as?
Ionising radiation.
55
Why are X-rays and gamma rays dangerous?
They can penetrate tissues, alter DNA and cause cancer.
56
How can we protect against X-ray and gamma ray exposure?
Use lead shielding and limit exposure duration.
57
Can light waves be reflected and refracted?
Yes, light waves can undergo both reflection and refraction.
58
How do you draw a ray diagram for reflection?
Draw incident and reflected rays meeting at a flat surface, with equal angles on either side of the normal.
59
How do you draw a ray diagram for refraction?
Show the ray bending at the boundary between two media, toward the normal when entering a denser medium.
60
What happens when light enters a denser medium?
It slows down and bends towards the normal.
61
What happens when light enters a less dense medium?
It speeds up and bends away from the normal.
62
What is a rectangular block used for in refraction experiments?
To observe refraction through parallel sides where the emergent ray is displaced but parallel.
63
What is the purpose of using a semi-circular block in refraction experiments?
To prevent refraction at the curved edge, allowing direct measurement of angles at the flat face.
64
What is the role of triangular prisms in light experiments?
To demonstrate how white light disperses into a spectrum through refraction.
65
What is the formula linking refractive index, angle of incidence and refraction?
n = sin(i) / sin(r)
66
How do you measure the refractive index of glass using a glass block?
Measure angles of incidence and refraction, then apply n = sin(i)/sin(r).
67
What is total internal reflection?
When light reflects entirely within a denser medium at an angle greater than the critical angle.
68
Where is total internal reflection used?
In optical fibres and right-angled prisms for signal transmission or reflection.
69
Why is total internal reflection important in optical fibres?
It keeps light signals inside the fibre, even when bent, ensuring efficient data transfer.
70
What is the critical angle?
The smallest angle of incidence at which total internal reflection occurs.
71
When does total internal reflection occur?
When light moves from a more to a less optically dense medium at an angle greater than the critical angle.
72
What is the formula linking critical angle and refractive index?
sin(c) = 1 / n
73
What happens to light at the critical angle?
It travels along the boundary between the two media.
74
What type of wave is sound?
A longitudinal wave.
75
Can sound waves be reflected?
Yes, this is heard as an echo.
76
Can sound waves be refracted?
Yes, when moving through layers of air with different temperatures or densities.
77
What is the unit of wave frequency?
Hertz (Hz), which means the number of cycles per second.
78
What is the unit of wavelength?
Metre (m).
79
What is the unit of wave speed?
Metres per second (m/s).
80
What is the unit of time period?
Seconds (s).
81
What is the unit of angle in wave and light studies?
Degrees (°).
82
How are longitudinal and transverse waves different?
In longitudinal waves, oscillations are parallel to wave travel; in transverse waves, oscillations are perpendicular to wave travel.
83
What do waves transfer?
Energy and information, not matter.
84
What is the equation for wave speed?
Wave speed = frequency × wavelength (v = f × λ).
85
What is the equation linking frequency and time period?
Frequency = 1 / time period (f = 1 / T).
86
How can wave equations be applied to both sound and light?
They can be used to calculate wave speed, frequency or wavelength when two of the values are known.
87
How does the Doppler effect change frequency and wavelength?
Frequency appears higher and wavelength shorter when a source moves toward an observer; the opposite occurs when it moves away.
88
Why does the Doppler effect occur?
Because motion between the source and observer alters the spacing of wavefronts reaching the observer.
89
Can all waves reflect and refract?
Yes, both reflection and refraction occur in all wave types when they hit a boundary.
90
What is the electromagnetic spectrum?
A range of transverse waves including radio, microwave, infrared, visible, ultraviolet, X-rays, and gamma rays.
91
What is the order of the electromagnetic spectrum by decreasing wavelength?
Radio, microwave, infrared, visible, ultraviolet, X-ray, gamma ray.
92
What is the order of visible light colours from longest to shortest wavelength?
Red, orange, yellow, green, blue, indigo, violet.
93
What is ultraviolet used for?
Fluorescent lamps and sterilisation.
94
What is a danger of microwave radiation?
Internal heating of body tissues.
95
What is a danger of infrared radiation?
It can cause skin burns.
96
What is a risk of ultraviolet exposure?
Damage to skin cells and possible blindness.
97
What is a risk of gamma ray exposure?
They can cause mutations and cancer.
98
How can exposure to microwave radiation be reduced?
Use shielding and avoid prolonged exposure.
99
How can we reduce the risk from infrared radiation?
Limit exposure and use protective barriers or clothing.
100
How can we protect against ultraviolet radiation?
Use sun cream, protective clothing and UV-blocking sunglasses.
101
How can we protect against gamma and X-rays?
Use lead shielding and limit exposure time.
102
Can light be reflected and refracted?
Yes, light undergoes both reflection and refraction.
103
What does the law of reflection state?
The angle of incidence equals the angle of reflection.
104
What practical can be used to study light refraction?
Use rectangular or semi-circular blocks and shine a light ray through them, measuring angles.
105
What shape of block helps study total internal reflection?
A semi-circular block allows the incident ray to hit a flat surface from within at various angles.
106
How does a triangular prism affect light?
It disperses white light into a spectrum due to varying refraction of different wavelengths.
107
How do you find the refractive index of glass in a practical?
Shine a ray into a glass block, measure angles of incidence and refraction, and apply n = sin(i)/sin(r).
108
What is the formula for critical angle?
sin(c) = 1 / n, where n is the refractive index.
109
Why is total internal reflection important in fibre optics?
It keeps light bouncing within the fibre, preventing signal loss.
110
What is the frequency range of human hearing?
20 Hz to 20,000 Hz.
111
How can the speed of sound in air be measured?
Make a sound near a large wall, measure the time for the echo to return, and use speed = distance / time.
112
Why must the distance be doubled when measuring speed of sound with an echo?
Because the sound travels to the wall and back, covering twice the measured distance.
113
How can an oscilloscope be used to display a sound wave?
By connecting it to a microphone, it shows a trace representing the waveform of the sound.
114
What does the vertical axis of an oscilloscope represent in sound experiments?
Amplitude, which indicates loudness.
115
What does the horizontal axis of an oscilloscope represent in sound experiments?
Time, which allows measurement of frequency from wave cycles.
116
How can you determine the frequency of a sound using an oscilloscope?
Measure the time period of one wave cycle and calculate frequency using f = 1 / T.
117
What does a higher frequency wave look like on an oscilloscope?
It has more wave cycles in the same time span—closer together.
118
What does a larger amplitude wave look like on an oscilloscope?
It has taller peaks and deeper troughs.
119
What does the pitch of a sound depend on?
The frequency of vibration of the sound source.
120
What happens to pitch when frequency increases?
The pitch becomes higher.
121
What does the loudness of a sound depend on?
The amplitude of vibration of the sound source.
122
What happens to loudness when amplitude increases?
The sound becomes louder.
