Question

An observer is standing $2.040km$ away from a source of sound. The velocity of sound in the medium is $340m{s}^{-1}$. The frequency of the sound is $500Hz$. Calculate the number of oscillations that the sound wave makes before it reaches that person.

• A. 3000
• B. 1000
• C. 6000
• D. 2000

Answer 1

The correct option is A 3000

The distance between the source and the observer, $s=2.040km$ = $2040m$.
The velocity of sound, $v=340m{s}^{-1}$.
The frequency of the sound, $f=500Hz$.
The time taken for the sound wave to reach the observer from the source is,
$t=\frac{s}{v}$

The number of oscillations in time $t$ will be, $n=tf$
$n=\frac{s}{v}f$
$n=\frac{2040\times 500}{340}$
$n=3000$.
Hence, the number of oscillations that the sound makes before it reaches the person would be 3000.