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Answer :

Speed (v) of sound = 339 m/s

Wavelength \( \lambda \) of sound = 1.5 cm = 0.015 m

We know that,

\( Speed \ of \ sound \ = \ Wavelength \ × \ Frequency \)

\( v \ = \ \lambda \ × \ \nu \)

\( v = \frac{v}{ \lambda } = \frac{339}{0.015} = 22600 \ Hz \) .

The frequency of audible sound for human beings lies between the ranges of 20 Hz to 20,000 Hz. The frequency of the given sound is more than 20,000 Hz, therefore, it is not audible.

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- A person has a hearing range from 20 Hz to 20 kHz. What are the typical wavelengths of sound waves in air corresponding to these two frequencies? Take the speed of sound in air as 344 m/s.
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- When a sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound production remains the same. Do you hear echo sound on a hotter day?
- Give two practical applications of reflection of sound waves.
- A stone is dropped from the top of a tower 500 m high into a pond of water at the base of the tower. When is the splash heard at the top? Given, \( g = 10 m/s^2 \) and speed of sound = 340 m/s.
- What is reverberation? How can it be reduced?
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- Explain how defects in a metal block can be detected using ultrasound.
- Explain how the human ear works.

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