During a fireworks show, a flash of light and a loud bang are produced at the same instant from each shell explosion.
A spectator is standing some distance away from the launch pad. Explain why the spectator sees the flash of light before hearing the bang.
A student records the time delay between seeing the light flash and hearing the bang for various fireworks launched from a barge that is moving along a straight river path.
| time from start / minutes | 0.0 | 3.0 | 6.0 | 9.0 | 12.0 | 15.0 |
|---|---|---|---|---|---|---|
| time between seeing flash and hearing bang / s | 4.5 | 3.0 | 1.5 | 3.0 | 4.5 | 6.0 |
(i) How many minutes after the start did the barge reach its closest point to the student?
How can you tell from the data that the barge never passed directly in front of the student (i.e. was never at a distance of zero from the student)?
At the start of the records (0.0 minutes), the barge was at a known landmark exactly 1530 m1530\text{ m}1530 m from the student. Using this information, calculate the speed of sound.
State one assumption made about the propagation of light or sound in your calculation for (b)(iii).
Some waves are longitudinal; some waves are transverse. Some waves are electromagnetic; some waves are mechanical.
Describe the light waves of the flash and the sound waves of the bang by copying the table below and putting ticks (✓\checkmark✓) in the correct boxes to indicate which classifications apply to each.
| light waves | sound waves | |
|---|---|---|
| longitudinal | ||
| transverse | ||
| electromagnetic | ||
| mechanical |
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.