Sound waves from a loudspeaker spread nearly uniformly in all directions if the wavelength of the sound is much larger than the diameter of the loudspeaker.
(a) Calculate the frequency for which the wavelength of sound in air is ten times the diameter of the speaker if the diameter is 20 cm.
(b) The sound is essentially transmitted in the forward direction if the wavelength is much shorter than the diameter of the speaker. Calculate the frequency at which the wavelength of the sound is one-tenth of the diameter of the speaker described above. Take the speed of the sound to be 340 m/s.
Answers
Answer ⇒ 170 Hz. and 17kHz.
Explanation ⇒
(a) Given conditions, the speed of sound (V) = 340 m/s
Now, the diameter of the speaker (d) = 20 cm
∴ Wavelength of the sound wave = 10 × 20 cm
= 200 cm
= 2.0 m .
Hence the frequency of the sound wave ν =V/
= 340/2 Hz
= 170 Hz .
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(b) In the second case the wavelength of the sound = 20/10 cm
= 2 cm
= 0.02 m
Hence the frequency of the sound waves ν' =V/
= 340/0.02 Hz
= 17000 Hz
= 17 kHz
Hope it helps.
Answer:
Explanation:
a) Given conditions, the speed of sound (V) = 340 m/s
Now, the diameter of the speaker (d) = 20 cm
∴ Wavelength of the sound wave = 10 × 20 cm
= 200 cm
= 2.0 m .
Hence the frequency of the sound wave ν =V/
= 340/2 Hz
= 170 Hz .
_________________________________
(b) In the second case the wavelength of the sound = 20/10 cm
= 2 cm
= 0.02 m
Hence the frequency of the sound waves ν' =V/
= 340/0.02 Hz
= 17000 Hz
= 17 kHz