Take the speed of sound to be 340 m/s.A thunder clap is heard about 3 s after the lightning is seen.The source of both light and sound is:
A)moving overhead faster than the speed of sound
B)emitting a much higher frequency than is heard
C)emitting a much lower frequency than is heard
D)about 1000 m away
E)much more than 1000 m away

Question

Quizplus · Accepted Answer

We can use the fact that the speed of sound is approximately 340 m/s to estimate the distance between the observer and the source of the sound. Since the thunder clap is heard 3 seconds after the lightning is seen, we know that the sound has traveled a distance of:

Distance = Speed x Time = 340 m/s x 3 s = 1020 m

Therefore, the source of the thunder clap must be at least 1020 m away from the observer. Choice D is the only option that satisfies this condition. Choices A, B, and C are all incorrect because they pertain to properties of the source that do not explain the delay between the light and sound signals.

Take the Speed of Sound to Be 340 M/s