Question

Your friend says that the wavelength of light waves is less in water than in air. Do you agree or disagree, and why?

Answer 1

Yes, the wavelength is less in water because the speed of light is less there than it is in air.
Frequency f alawys stays the same, and
(frequency) x (wavelength) = (speed of light)
When the speed of light goes down, so does the wavelength