Question

The frequency of a man's voice is $300Hz$ and its wavelength is $1meter$. If the wavelength of a child's voice is $1.5m$, then the frequency (in $Hz$ ) of the child's voice is:

Answer 1

Given, Frequency of the man’s voice, $f_1=300Hz$

Wavelength of the man’s voice, ${\lambda }_1=1m$

Wavelength of the child’s voice, ${\lambda }_2=1.5m$

As we know, velocity of sound is constant for both man and child, $\upsilon =f\lambda$

$\Rightarrow f_1{\lambda }_1=f_2{\lambda }_2$

$\left(300\right)\left(1\right)=f_2\left(1.5\right)$

$f_2=200Hz$

Final answer: $200Hz$