Physics 0625 · IGCSE · Sound

Sound — practice question

The boat race begins on the sea, yet it is near the shore. Fig. 9.1 shows the boats as the race begins. On land, a cannon gives a very loud bang to signal the start. A flash of light occurs at exactly the same moment as the bang.
(a(i))[1]

At the beginning of the race, the sailors look out for the flash of light from the cannon. Suggest why the sailors watch for the flash of light rather than listen for the bang.

(a(ii))[3]

Calculate the speed of sound.

(a(iii))[1]

The speed of sound found in a(ii) is lower than expected. Suggest a reason for this difference.

(b)[2]

State the term for the second bang and explain how it is produced.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: Light travels faster than sound OR flash / light seen before bang heard

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