Electromagnetic Spectrem help - Reflection of radiation.

Hi, I am wondering what happens to the wavelength and frequency of electromagnetic radiation if it is reflected and why.
I read somewhere that it changes but don't understand why.
Also wondering if electromagnetic radiation changes by the distance travelled as I thought that the wavelength decreased over time.
If anybody could shed light on this I would be very happy.
Thanks!

Reply 1

spread_logic_not_hate

With regard to the reflection question, nothing happens to the wavelength or frequency of light that is reflected - this only changes if it is refracted.

EM radiation doesn't change wavelength as it travels EXCEPT in the case of red or blue shifting, but that is related to the expansion of the universe and is only noticable on galactic length scales (i.e. millions of light years)