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Independent final check

Page 03

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Explain without the key

describe / calculate

Final check

A boat sounds its horn 765 m from a cliff, and the crew hears an echo. The speed of sound in air is 340 m/s. (a) Describe what the echo is. (b) Calculate how long after the horn sounds the crew hears the echo.

describe: give the features or what happens. calculate: work out the answer from the data.

Give your answer with its unit

Type numbers like 0.25 or 2.5x10^-3. Put the unit in its own box, for example g, cm3 or m/s. Leave the unit box empty if the quantity has no unit.

(b) Time to hear the echo
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Scope and sources

Cambridge IGCSE Physics 0625 · 2026–2028 v2 · Original learning materials.

Cambridge IGCSE Physics 0625 (2026–2028): 3.4.6, 3.4.8, 3.4.9; Supplement 3.4.12. The speed of sound in air, water and steel (3.4.5) is SOUND01’s.

Apparatus, amounts and times in the experiment are illustrative. Real practical work follows a teacher-approved safety method.

Official Cambridge syllabus