A person burned a firecracker in front of a cliff and heard its echo 5

A person burned a firecracker in front of a cliff and heard its echo 5 s after it burst. The distance of the cliff from the person, if the speed of the sound is 340 m/s, is close to

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1700 m

170 m

85 m

850 m

Answer is Right!

Answer is Wrong!

This question was previously asked in

UPSC CDS-1 – 2023

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The time taken for the echo to be heard is the time it takes for the sound to travel from the person to the cliff and then back to the person. The total distance covered by the sound is therefore twice the distance between the person and the cliff. Given the speed of sound (v) is 340 m/s and the total time (t) for the echo is 5 s, the total distance (d_total) is v × t = 340 m/s × 5 s = 1700 m. The distance to the cliff (d_cliff) is half of the total distance: d_cliff = d_total / 2 = 1700 m / 2 = 850 m.

The total distance covered by an echo is twice the distance to the reflecting surface. Distance = Speed × Time.

Echo is the reflection of sound waves from a surface. The time delay between the original sound and the echo is used to determine the distance of the reflecting surface. This principle is used in sonar and ultrasound imaging.

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