Question

When echo is heard ? (A) If the time interval between original sound and reflected sound is more than 1/10 s. (B) If the time interval between original sound and reflected sound is less than 1/10 s. (C) If the tme interval between original sound and reflected sound is less than /150 s . (D) If the time interval between original sound and reflected sound is 1/150 s.

GSEB - Class 9 Chapter - 2. Wave Motion and Sound Page 23

Answer 1

answer is (A) if the time travel between original and reflected sound is 0.1 s

Answer 2

Option (A) is correct . When the time interval between the original sound and reflected sound is more than 0.1 s