Question

$\large \textbf {PHYSICS \: QUESTION}$

-Calculation of minimum distance to hear an echo. Explain

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Answer 1

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$\underline\bold{\huge{ANSWER \: :}}$

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1] INTRODUCTION TO ECHO

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✔ Echo refers to the repetition of sound caused by the reflection of sound waves from a distant reflector.

✔ The sound after striking a hard surface reaches the listener's ear in a different feeling.

✔ Repeated echo however results in REVERBERATION.

✔ When we shout in a big empty auditorium, we first hear the original sound and after a little while, we hear the reflected sound of the shout. This reflected sound is termed as "ECHO".

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2] CALCULATION RELATED TO IT

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(A) MINIMUM DISTANCE (WHEN SPEED OF SOUND IN AIR IS 340 m/s)

The speed of sound in air is roughly 340 m/s.

Persistence of sound in our brain = 0.1 second.

So, the distance traversed by sound in 0.1 second is (340×0.1) m = 34 m.

So, the minimum distance of the reflector from the source of sound will be half of 34 m or 17 m.

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(B) MINIMUM DISTANCE (WHEN SPEED OF SOUND IN AIR IS 332 m/s)

The speed of sound in air is roughly 332 m/s.

Persistence of sound in our brain = 0.1 second.

So, the distance traversed by sound in 0.1 second is (332×0.1) m = 33.2 m.

So, the minimum distance of the reflector from the source of sound will be half of 33.2 m or 16.6 m.

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Answer 2

❤ HERE IS YOUR ANSWER ❤

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◼ Assuming speed = 340 m/s ◼

The speed of sound in air is roughly 340 m/s. 

Persistence of sound in our brain = 0.1 second. 

So, the distance traversed by sound in 0.1 second is (340×0.1) m = 34 m. 

So, the minimum distance of the reflector from the source of sound will be half of 34 m or (34/2) m or 17 m.

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