« on: Yesterday at 12:45:43 »
I agree that the definition above says that, but it is wikipedia, and I think they mean frequency change and associated wavelength change and not the case of wavelength change associated only with refraction and not frequency change. I'm saying wiki is wrong here.Quote from: wikiThe Doppler effect (or the Doppler shift) is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842.https://en.wikipedia.org/wiki/Doppler_effect
From the definition above, Doppler effect can happen if wavelength changes even if the frequency stays the same, which means that the propagation speed also changes accordingly.
From oxford dictionary (top of list if you google "what is doppler effect"):
"[physics:] an increase (or decrease) in the frequency of sound, light, or other waves as the source and observer move toward (or away from) each other. The effect causes the sudden change in pitch noticeable in a passing siren, as well as the redshift seen by astronomers."
Britanica: "Doppler effect, the apparent difference between the frequency at which sound or light waves leave a source and that at which they reach an observer, caused by relative motion of the observer and the wave source."
"a change in the frequency with which waves (as of sound or light) from a given source reach an observer when the source and the observer are in motion with respect to each other so that the frequency increases or decreases according to the speed at which the distance is decreasing or increasing"
"The Doppler effect describes the shift in the frequency of a wave sound when the wave source and/or the receiver is moving."
Pretty much every place except wiki says it's a frequency shift and does not consider a wavelength change without frequency change to be an example of Doppler effect.
The following users thanked this post: hamdani yusuf