A man fires a bullet standing between two cliffs. First echo is heard after 3 s and second echo is heard after 5 s. If the velocity of sound is 330 m/s, then the distance between cliffs is :

Question

A man fires a bullet standing between two cliffs. First echo is heard after 3 s and second echo is heard after 5 s. If the velocity of sound is 330 m/s, then the distance between cliffs is : (A) 660 m (B) 990 m (C) 1320 m (D) 1950 m

Tardigrade Admin · Accepted Answer

Echo is defined as the reflection of a sound wave back to its source in sufficient strength and with a sufficient time lag to be separately distinguished.
Time

= \frac{distance}{speed}

Given that first echo is heard after

3 s

, hence time taken for the echo to travel from first cliff to man is

t_{1} = \frac{3}{2} = 1.5 s

Similarly, time taken for the echo to travel from second cliff to man is

t_{2} = \frac{5}{2} = 2.5 s

Distance between man and first cliff is

d_{1} = time \times velocity = 1.5 \times 330 = 495 m

Distance between man and second cliff is

d_{2} = time \times velocity = 2.5 \times 330 = 825 m

Hence, distance between two cliff's is

= d_{1} + d_{2} = 495 + 825 = 1320 m

Q. A man fires a bullet standing between two cliffs. First echo is heard after 3s and second echo is heard after 5s. If the velocity of sound is 330m/s, then the distance between cliffs is :

660 m

990 m

1320 m

1950 m

Q. A man fires a bullet standing between two cliffs. First echo is heard after $3 s$ and second echo is heard after $5 s$ . If the velocity of sound is $330 m / s$ , then the distance between cliffs is :