How Do Wavelength and Frequency Relate in Different Mediums?

[Halimeek]

i need help in these equations please :

Q1 - if there is a frequency 440Hz for a sound wave in air with velocity
430 m/s calculate wavelength and wavenumber.
---------------------
Q2- the speed of light about 3X 10⁸ m/s find the wave length and wave number for the frequency 5x 10¹⁴ Hz
---------------------
Q3-A afish looking out of water with angular 37° what is the angulat of vision ?
(n1= i-33 for water and n2 = 1 for air)
----------------------
Q4- A focal length for mirror 20 cm and there is a body away from this mirror about 40 cm . in what lenghth we can see photo ?

 

[Mike Pemulis]

The first two are similar, so let's start there. What's the relationship between wavelength and frequency?

Also, would you mind writing out Q3 and Q4 a little more clearly?