The speed of water waves is 30cm/s in deep water & 15cm/s in shallow water. If the wavelength in deep water is 1.0cm, what is the wavelength in shallow water?

Question

(v2/v1)=(wavelength2/wavelength1)
Therefore (15/30)=(wavelength2/1)
- 15=30wavlength2
-Wavelength2=0.5cm/s

A) Is that correct?
B) I'm confident I chose the right values for 1 & 2 because I know that the wavelength gets shorter as the water gets shallower but otherwise, when it's not specified, how do I know what is 2 & what is 1?

Thanks a ton :)

Answer 1

the frequency (and period) do not change)

distance = speed * time
or
wavelength = speed * period

1 = 30 T so T = 1/30
L = 15 T = 15(1/30) = 1/2
so I agree

Answer 2

Ok excellent, thank you :)