To hear the echo of a sound distinctly, the reflecting surface should be at a minimum distance of ___ from the observer.
A. 15.5 m
B. 16.6 m
C. 11.2 m
D. 18.6 m
Answer:C
To hear the echo of a sound distinctly, the reflecting surface should be at a minimum distance of ___ from the observer.
A. 15.5 m B. 16.6 m C. 11.2 m D. 18.6 m