Question

If a person is standing in front of a tall building 18m away from him. He would hear___________.​

Answer 1

Answer:

hope this helps you :)

Explanation:

The associated phenomenon is known as Echo. We get echoes because of the reflection of sound. The reflected sound reaches the observer after a time 2d/v, where d is the distance of the reflecting wall from the source. For the human ear. this time must be at least 0.1 second to ensure that the reflected sound does not get mixed up with the direct sound. Since the velocity of sound in air is nearly 330 ms-1, we must have

2d/330 > 0.1

or   d > 16.5 m

Since the building in this case, is at a distance of 18 m, we can hear the reflected sound clearly. We thus get a clear echo in this case.