An observer is positioned at the finishing line for a $100\,\text{m}$ race. He wants to measure the winner’s time. He begins his stop-watch the moment he sees the smoke from the starting gun, rather than when he hears the bang. What is the reason for doing this?
- ALight travels much faster than sound.
- BThere is a risk he might respond to an echo from a wall.
- CHumans react slower to sound than to light.
- DHumans react more quickly to sound than to light.