Question

Voices of swimmers at a pool travel 400 m/s through the air and 1,600 m/s underwater. The wavelength changes from 2 m in the air to 8 m underwater. How has the change in media affected the frequency of the wave? It increased. It decreased. It stayed the same. It cannot be calculated.

Answer 1

Answer : Frequency stayed the same.

Explanation :

Voices of swimmers at a pool travel through the air at a speed of 400 m/s and 1600 m/s.

The wavelength changes from 2 m in the air to 8 m underwater.

We know that the relation between speed and the wavelength.

$v=\nu\times \lambda$

$\nu=\dfrac{v}{\lambda}$

$\nu$ is the frequency.

$\lambda$ is the wavelength.

Frequency through air, $\nu_a=\dfrac{400\ m/s}{2\ m}=200\ Hz$

Frequency through water, $\nu_w=\dfrac{1600\ m/s}{8\ m}=200\ Hz$

So, the frequency of voice of swimmers stayed the same.

Hence, the correct option is (C) " It stayed the same".

Answer 2

The frequency of a sound is whatever frequency leaves the source. It doesn't change.

Voiced of swimmers at the pool don't change frequency in or out of the water. Only their speed and wavelength change.