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Q115
(CDS-I/2023)
Science & Technology › Basic Science (Physics, Chemistry, Biology) › Waves and acoustics
Answer Verified
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
Result
Your answer:
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·
Correct:
D
Explanation
To calculate the distance of the cliff, we use the physics of sound echoes. An echo is heard when sound travels from the source to a reflecting surface and back again. Therefore, the total distance traveled by the sound wave is twice the distance (2d) between the person and the cliff. The relationship is given by the formula: Distance (d) = (Speed!7!7 Time) / 2. Given that the speed of sound (v) is 340 m/s and the time (t) taken to hear the echo is 5 seconds, the total distance covered by the sound is 340 m/s!7 5 s = 1700 m. Since this represents the round-trip distance, the actual distance to the cliff is 1700 m / 2 = 850 m. This calculation confirms that the cliff is located 850 meters away from the person.
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