A timekeeper stands at the finish line of a 200 m running track. They start their stopwatch when they see the flash of the starter's pistol rather than when they hear the bang.
What is the reason for doing this?
Light travels much faster than sound.
There is a risk that the sound wave will be absorbed by the air.
Humans react slower to auditory cues than to visual cues.
The pistol releases the flash a fraction of a second before the sound is created.
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.