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Question 15

A public fireworks display is held in a park near a range of steep hills. An observer stands a distance of 600 m600\text{ m}600 m from where a firework explodes. The observer sees a bright flash of light and then hears a loud bang.

a.

Explain why there is a short time delay between seeing the flash of the explosion and hearing the bang.

[2]
b.

Shortly after hearing the first loud bang, the observer hears a second, quieter bang. Which phenomenon is responsible for this second sound?

  • Diffraction of the sound around the hills
  • Dispersion of the sound in the air
  • Reflection of the sound from the hills
  • Refraction of the sound in the atmosphere
[1]
c.

Another observer is also standing 600 m600\text{ m}600 m away from the fireworks. She uses a stopwatch to measure the time delay between seeing the flash and hearing the first bang. Her measurements are shown in the table below:

MeasurementTime delay / s\text{s}s
11.9
21.7
31.8
42.0
51.6

Use these measurements to calculate an accurate value for the speed of sound.

[3]
Markscheme

Sound Questions

  1. IGCSE
  2. /Physics
  3. /Sound

295 exam-style questions on CIE IGCSE Physics Sound, covering Sound. Each one has a worked solution and a mark scheme showing where the marks go.

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