Question

Given that sound travels in air at $340\text{m/s}$. In air, a sound source is producing a wave of wavelength $34\text{cm}$. If the same source is put in a water tank, what would be the wavelength of sound wave in water?

$[$Speed of sound in water is $1360\text{m/s}]$

• A. $0.34\text{m}$
• B. $1.36\text{m}$
• C. $3.4\text{m}$
• D. $13.6\text{m}$

Answer 1

The correct option is B $1.36\text{m}$

We know that, frequency does not depend on medium, it depends on the source.

Also, speed of sound,
$v=\lambda f$

For same source, $v\propto \lambda$

$\Rightarrow \frac{v_1}{v_2}=\frac{{\lambda }_1}{{\lambda }_2}$

$\Rightarrow \frac{340}{1360}=\frac{0.34}{{\lambda }_2}$

$\Rightarrow {\lambda }_2=1.36\text{m}$