Question

How far does light travel in the time it takes sound to travel 1 cm in air at 20°c?

Answer 1

The speed of sound at
`20^(\circ)C` is approximately v=343 m/s. The distance covered by the sound wave is

`s=1 cm=0.01 m`
And the time it takes is

`t= (S)/(v)= (0.01 m)/(343 m/s)=2.9 \cdot 10^(-5) s`

Now we want to find how far the light travels during this time. Light travels at speed
`c=3 \cdot 10^8 m/s`, therefore the distance it covers during this time is

`S=ct = (3 \cdot 10^8 m/s)(2.9 \cdot 10^(-5) s)=8700 m`