Physics 0625 · syllabus 3.1
Cambridge IGCSE Physics 0625 — General properties of waves topical past papers
How waves carry energy but not matter: amplitude, wavelength, frequency and v = fλ, transverse and longitudinal waves, and reflection, refraction and diffraction.
- Questions
- 671
- Years
- 2009–2026
- With mark scheme
- 100%
- Questions 2022–2026
- 228
Anyone can browse these pages. Opening the questions and their mark schemes takes a free Momentum account.
What General properties of waves covers
A wave carries energy from place to place without carrying matter along with it: the water, rope or spring moves back and forth about its rest position while the wave travels on. Waves are described by their amplitude, the largest displacement from rest; their wavelength, the distance between neighbouring crests or troughs; their frequency, the number of waves passing a point each second, in hertz; and their speed, linked to the other two by v = fλ. A wavefront joins points on the same crest and is drawn at right angles to the direction of travel.
In a transverse wave the vibrations are at right angles to the direction the wave travels: light and every other electromagnetic wave, water waves and seismic S-waves behave like this. In a longitudinal wave the vibrations are along the direction of travel, making compressions and rarefactions: sound and seismic P-waves are longitudinal. A slinky spring shows both, depending on whether you shake it from side to side or push it in and out.
All waves can be reflected, refracted and diffracted, and a ripple tank shows each one. Waves reflect from a straight barrier at the angle at which they arrive. Passing into shallower water they slow down, so their wavelength shortens while their frequency stays the same, and if they cross the boundary at an angle they change direction: that is refraction. Passing through a gap or round an edge they spread out: that is diffraction. Extended candidates explain that a gap about the same size as the wavelength diffracts waves the most, and that longer wavelengths bend further round an edge.
In the syllabus
The headings this topic has in the Cambridge International 2026–2028 syllabus, as the board prints them.
- 3.1 General properties of waves
What you should be able to do
- Mark amplitude, wavelength, crests, troughs and wavefronts on diagrams of waves
- Use v = fλ, converting kHz to Hz and cm to m where needed
- Tell transverse waves from longitudinal waves and give examples of each
- Describe how a ripple tank shows reflection, refraction and diffraction, and draw the wavefronts in each case
- Explain refraction at a change of depth as a change of speed and wavelength at constant frequency
- Describe how the width of a gap and the wavelength affect diffraction (Extended)
Key ideas
- Wave speed v = fλ: v in m/s, f in Hz, λ in m
- Transverse: vibrations at right angles to the direction of travel; longitudinal: vibrations along it
- Waves transfer energy, not matter
- Refraction: the speed changes at a boundary; the frequency stays the same, so the wavelength changes
- Diffraction is greatest when the gap is about the same size as the wavelength (Extended)
How General properties of waves has been examined
From 2022 to 2026, General properties of waves was on Paper 3 · Theory (Core) in 14 of 14 exam series, worth about 8% of that paper’s marks.
| Paper | Questions | Share of marks | Series |
|---|---|---|---|
| Paper 1 · Multiple Choice (Core) | 90 | 7% | 14 of 14 |
| Paper 2 · Multiple Choice (Extended) | 87 | 7% | 14 of 14 |
| Paper 3 · Theory (Core) | 28 | 8% | 14 of 14 |
| Paper 4 · Theory (Extended) | 22 | 7% | 10 of 14 |
| Paper 6 · Alternative to Practical | 1 | 1% | 1 of 14 |
Momentum’s own count, over the questions in its bank for these years: a series is one exam session, every zone included, and a question filed under two chapters counts in both. Median marks per question: 1. The bank files this topic together with neighbouring ones, so these figures count every question in its chapters, including some on those topics.
Filed in Momentum under: Waves and Sounds.
A worked example
A dipper in a ripple tank vibrates at 8.0 Hz. A student measures the distance across six complete wavelengths as 15 cm. Find the speed of the waves. The waves then pass into shallower water, where their speed is 0.12 m/s; find their new wavelength.
- One wavelength = 15 cm ÷ 6 = 2.5 cm = 0.025 m
- Speed v = fλ = 8.0 × 0.025 = 0.20 m/s
- In the shallower water the frequency is still 8.0 Hz, so λ = v/f = 0.12 / 8.0 = 0.015 m
- Check: the waves slowed down, so their wavelength shortened, from 2.5 cm to 1.5 cm
Answer: 0.20 m/s; the wavelength in the shallower water is 1.5 cm
Written by Momentum for this page, with its own numbers; it is not taken from a past paper.
Mistakes that cost marks
- Measuring the wavelength from a crest to the next trough — that is half a wavelength; measure crest to crest or trough to trough
- Measuring the amplitude from crest to trough — amplitude runs from the rest position to a crest, so it is half that height
- Saying the frequency changes when a wave refracts — the source sets the frequency; only the speed and the wavelength change
- Drawing diffracted wavefronts closer together or further apart — diffraction leaves the wavelength unchanged; only the shape of the wavefronts changes
- Calling sound transverse or light longitudinal — sound is longitudinal, while light and all other electromagnetic waves are transverse
Exam technique
- When drawing reflected, refracted or diffracted waves, keep the wavefront spacing right: unchanged after reflection and diffraction, closer together in shallower water
- Convert the units before using v = fλ, and rearrange the equation before substituting
- When asked to distinguish transverse and longitudinal waves, compare the direction of vibration with the direction the wave travels, and give an example of each
- For diffraction, say how the gap compares with the wavelength, not just whether the gap is narrow
Practising in Momentum
- Every question in a chapter as one list, from every paper and year in the bank, newest first or shuffled.
- Each question turns over to its own part of the mark scheme, where the board published one.
- Narrow by paper, year, session, zone and marks, and star the questions worth keeping.
- Pick chapters, a number of questions and a time, and the exam builder draws a mock to sit and mark.
Past-paper questions and mark schemes are the copyright of Cambridge International. Momentum shows them to signed-in learners for revision and does not publish them on these pages.