Question

Human ears can sense sound waves travelling in air having wavelength of ________.

• A. ${10}^{-3}m$
• B. ${10}^{-2}m$
• C. $1m$
• D. ${10}^{2}m$

Answer 1

The correct option is C $1m$

Human ears can sense sound waves travelling in air whose frequencies $f$ lie in the range of $20Hz$ to $20kHz$

The average speed $v$ of sound in air is $335m/s$

Wavelength $\lambda =\frac{v}{f}$

Hence the wavelength range of audible sounds is $\frac{335}{20000}$ $to$ $\frac{335}{20}$

That is $1.675\times {10}^{-2}$ metres to $16.75$ metres

You can see that among all the 4 options given, only $1m$ fits in the audible range.