Waves: GCSE Combined Science
Transverse and longitudinal waves, v = fλ, the electromagnetic spectrum, uses and hazards, the infrared practical, and sound
The short version
Contrast transverse and longitudinal, use v = fλ, order the EM spectrum, recall uses and hazards, and describe the infrared required practical.
Key idea
Examples: water ripples, waves on a string, all EM waves
Grade 2–3: A duck on a pond bobs; it is not swept to the beach. Waves carry energy, not the water.
Grade 5–6: I can name crests and troughs for transverse, compressions and rarefactions for longitudinal.
Grade 9: Light is fastest in vacuum - it does not need air. Sound is not transverse. Mechanical waves need a medium; EM waves do not.
Go a bit deeper
Period T is the time for one wave, in seconds
Grade 2–3: Wavelength is crest to crest. Frequency is how many waves each second.
Grade 5–6: I use v = fλ and T = 1/f. I count waves in 10 s then divide to get f.
Grade 9: Amplitude links to energy (louder, brighter) but not to speed in the simple Combined model. In one medium, double f and you halve λ. Convert cm to m before substituting.
Worked example
Worked example
Grade 2–3: A duck on a pond bobs; it is not swept to the beach. Waves carry energy, not the water. Grade 5–6: I can name crests and troughs for transverse, compressions and rarefactions for longitudinal. Grade 9: Light is fastest in vacuum - it does not need air. Sound is not transverse. Mechanical waves need a medium; EM waves do not.
Lessons in this topic
- Transverse longitudinal
- Wave properties v=fλ
- EM spectrum
- Uses and hazards of EM
- Infrared radiation required practical
- Sound Combined
In the app each lesson is video (when we have a real YouTube id) then intro, learn and summary steps.
What the examiner wants
Oscillations are perpendicular to energy transfer in transverse waves and parallel in longitudinal. EM waves are transverse and travel at the same speed in vacuum. Sound needs a medium.
Try these questions
Cover the answers and have a go first. Worked solutions are underneath.
In a transverse wave, oscillations are
Sound in air is
A wave has f = 4.0 Hz and λ = 0.50 m. Speed is
Period T of a 50 Hz wave is
Common mistakes
- Do not say sound is transverse. Do not say light needs air.
- Convert cm to m before substituting into v = fλ.
- Do not write that microwaves are ionising because ovens cook food. That is heating, not ionisation.
- A random list of uses with no property often misses the "explain" marks. Pair property -> use.
Answers and working
Frequently asked questions
Is GCSE Waves on Combined Science and Triple?
Waves is on Combined Science and on Triple Physics. Progress is shared in the ReviseEasy app.
Which exam board is this Waves page for?
The ideas are board-agnostic for AQA, Edexcel, OCR, WJEC and CCEA. Paper lengths and question numbers differ — check your specification.
Is Waves Foundation or Higher?
The core ideas appear on both tiers. Higher papers add extra application and some HT-only detail, marked in lessons with a Higher badge.
Learn, try, get feedback, fix the mistake
Open the stepped lesson, then the quiz with hints. Required-practical and calculation questions use the same method you will need in the paper.
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