# Doppler effect for light only depends upon the relative motion of the source of sound and observer?

How would doppler effect for light only depend on relative motion of source and observer ?

While studying my text says :

" Doppler effect for sound depends upon the relative motion of source and listener and it also depends upon that which one of these is in motion.

Where is The Doppler effect for light depends only upon the relative motion of the source of sound and observer"

I understand it for the sound but for light I don't get two things written

1. why doppler effect for light depends on relative motion of sound ? and not light ?

2. why would it only depend on relative motion of source and observer?

• "The Doppler effect for light depends only upon the relative motion of the source of sound and observer" that must be a mistake. it should read :"light" – anna v Mar 31 '17 at 10:29
• @Anna V that's what I was confused with – Physicsapproval Mar 31 '17 at 11:13