# Refraction : freq remains unchanged

#### momentum

this is my first post in this forum.
i have a question :
i have read that when light refracts into other medium its frequency remains unchanged but velocity and wavelength changes.

there is a formula to it : v=n*lamda (v=velocity,n=freq,lambda=wavelength)

Q1: why the freq remains unchanged ?

Q2: is it true for all waves (like sound, etc ) ?

thank you

Last edited:
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#### dextercioby

Homework Helper
YES.The frequency is determined by the source.By the vibration of those electrons,or by the specific transition which occurs inside the atom.

Daniel.

#### momentum

i have some questions on social science, geography . will you please tell me some forum links where i could post questions on these topics. is there any forum like this which supports questions on social sc, geography,economis ?

#### Dr.Brain

Yes, the frequency means the cycles/sec , which as daniel said is determined by the source but the wavelength is the distance between two consecutive troughs/crests , when a light ray enters into the medium this length between crests/trough decreasses but the frequency remains the same. This happenes with all the electromagnetic waves and sound waves.

#### momentum

Yes, the frequency means the cycles/sec , which as daniel said is determined by the source but the wavelength is the distance between two consecutive troughs/crests , when a light ray enters into the medium this length between crests/trough decreasses but the frequency remains the same. This happenes with all the electromagnetic waves and sound waves.
thanks doctor. thats very beautiful .

#### dextercioby

Homework Helper
You can ask all your questions here.In this forum for "genetal physics" and in other specialized forums for other subjects.

Welcome ot PF !!

Daniel.

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