What is the minimum distance from a reflecting surface needed to hear a distinct echo, rather than a blurred, prolonged sound?

Please wait…

1. What is the minimum distance from a reflecting surface needed to hear a distinct echo, rather than a blurred, prolonged sound?

10 metres

13 metres

17 metres

21 metres

 Loading…

 

A distinct echo requires the reflecting surface to be at least about 17 metres away, giving enough time gap between the original sound and its reflection.