IGCSE 0625 / Section 3.1 / Core

The anatomy of a wave.

Drop a stone in a pond and rings race outward, yet a floating leaf only bobs in place. The ripples carry energy across the water without carrying the water itself. Describing that travelling disturbance is what wave features are for.

The key idea

A wave transfers energy without transferring matter. Its wavelength is the distance for one complete wave, its amplitude is the maximum displacement from rest, its frequency is the number of waves per second in hertz, and its period is the time for one wave.

Definition · learn the exact words

The wavelength is the distance between two adjacent points in step (one complete wave); the amplitude is the maximum displacement from the rest position; the frequency is the number of waves passing a point each second.

f = 1 ÷ T  (frequency in Hz, period in s)

A wave carries energy, not matter. Amplitude is measured from the middle, not crest to trough.

Section 01

Read a wave off the screen.

Change the amplitude and frequency and watch the wavelength and period respond.

Stage 1 · Learn

Check wave features

Four quick checks. Each correct answer earns XP and lights this skill on your star map.

Quick check+10 XP

The wavelength of a wave is...

Quick check+10 XP

The amplitude of a wave is...

Quick check+10 XP

Frequency is measured in...

Quick check+10 XP

A wave transfers...

Section 02

Four numbers describe any wave.

Wavelength, amplitude, frequency and period are linked, and frequency is simply one over the period.

f = 1 ÷ T
Worked example

A wave has a period of 0.20 s. Find its frequency.

Step 1 · Write the relationf = 1 ÷ T
Step 2 · Substitutef = 1 ÷ 0.20
Step 3 · Answerf = 5.0 Hz
Examiner trap

A wave transfers energy, not matter: the water, air or rope it travels through stays put on average. And amplitude is measured from the rest position to a crest, not all the way from a crest down to a trough.

Stage 2 · Exam

Exam-style questions

Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.

Finish the four checks above to unlock the exam questions
Exam style+20 XP

A wave has a period of 0.20 s. Its frequency is...

Exam style+20 XP

The amplitude of a water wave is correctly measured from...

Exam style+20 XP

Two waves travel at the same speed, but wave A has a longer wavelength than wave B. Wave A therefore has a...

Skill unlocked

Wave features, mastered.

The first wave skill is lit. Keep the chain going.

-Rank -Level -Score -Topics
Go deeper · practice
Six original Cambridge-style questions
Wavelength, amplitude, frequency and period, the f = 1/T relation, and the idea that waves carry energy not matter. Attempt each, then reveal the worked solution.
Stage 3 · master the unit
Waves challenge
Mixed questions across the whole unit, each one worth XP. Start this only when you feel confident across every topic in the unit, not just wave features.
Start the unit challenge →