

InterviewSolution
Saved Bookmarks
1. |
A person has a hearing range from 20 Hz to 20 kHz. What are the typical wavelength of sound waves in sir corresponding to these two frequencies ? Take the speed of sound in air as 344 m//s. |
Answer» Solution :(i) In the FIRST case: Speed, `v = 344 ms^(-1)` Frequency, `F = 20 Hz` And, Wavelength, `lambda = ?` (To be calculated) Now, `v = f xx lambda` So, `344 = 20 xx lambda` `lambda = (344)/(20)m` Wavelength, `lambda = 17.2m`...(1) (ii) In the second case: Speed, `v = 344 ms^(-1)` Frequency, `f = 20 KHZ` `= 20 xx 1000 Hz` (Because `1kHz = 1000 Hz)` `= 20000 Hz` And, Wavelength, `lambda = ?` (To be calculated) Now, `v = f xx lambda` So, `344 = 2000 xx lambda` `lambda = (344)/(20000)` Wavelength, `lambda = 0.0172m` ...(2) Thus, the wavelengths of SOUND in air corresponding to the frequencies of 20Hz and 20 kHz are 17.2m and 0.0172 m respectively. |
|