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.
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.
[tex]v=\nu\times \lambda[/tex]
[tex]\nu=\dfrac{v}{\lambda}[/tex]
[tex]\nu[/tex] is the frequency.
[tex]\lambda[/tex] is the wavelength.
Frequency through air, [tex]\nu_a=\dfrac{400\ m/s}{2\ m}=200\ Hz[/tex]
Frequency through water, [tex]\nu_w=\dfrac{1600\ m/s}{8\ m}=200\ Hz[/tex]
So, the frequency of voice of swimmers stayed the same.
Hence, the correct option is (C) " It stayed the same".
