Question

the time intervel between direct and reflected sounds to hear an echo is​

Answer 1

Answer:

Echo. ... This sound which we hear is called an echo. The sensation of sound persists in our brain for about 0.1 s. To hear a distinct echo the time interval between the original sound and the reflected one must be at least 0.1s.

Explanation:

Answer 2

We can hear only 10beats per second

so time=1/frequency=1/10=0.1

0.1 sec is the time interval between Direct and reflected sounds to hear an echo.