A rule of thumb for estimating the distance in kilometers between an observer and a lightning stroke is to divide the number of seconds in the interval between the flash and the sound by 3. Discuss whether or not this rule is correct.

I say it is correct because the speed of light is faster than the speed of sound, sound has a delay. (Am I heading in the right direction with this answer.)

1 answer

you are headed in the right direction.

Light also has a delay, but it is so short that the difference in arrival time is due entirely to the slow speed of sound, which is approximately

wait for it ...

1/3 km/sec!