All waves, as far as I know.
The Doppler effect is most noticed when it comes to three types of waves. They are water waves, sound waves and light waves.
The Doppler effect proves that sound travels in waves.
Sound Waves.
It only works with waves.
No. We observe the Doppler Effect in all forms of waves, including sound waves and all forms of electromagnetic radiation.
The Doppler effect is a phenomenon observed whenever the source of waves is moving with respect to an observer. The Doppler effect can be described as the effect produced by a moving source of waves in which there is an apparent upward shift in frequency for the observer and the source are approaching and an apparent downward shift in frequency when the observer and the source is receding. The Doppler effect can be observed to occur with all types of waves - most notably water waves, sound waves, and light waves.
I fear you're confused - BUT : The Doppler effect is similar for both sound waves and electromagnetic radiation (light, radar).
Both.
Both.
yes it is true for all waves.
yes
It is typical of all waves.