Is Doppler Effect Infinite when Wave Velocity Equals Emitter Velocity?

AI Thread Summary
The discussion centers on the Doppler effect and its implications when the wave velocity equals the emitter velocity. It is theorized that if the emitter travels at the speed of sound, the wavelength approaches zero, resulting in an infinite frequency. This phenomenon explains the sonic boom experienced when a jet reaches sound speed. Participants also inquire about the demonstration of the Doppler formula, particularly in nonrelativistic cases, referencing the Doppler-Fizeau formula. The conversation highlights the complexities of applying these concepts in different contexts within physics.
Raparicio
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Hello.

I have a question on Doppler effect. When the wave has the same velocity that the emisor, u have this:

f= \frac {\partial {(Vs-Vo)}} {\partial {(Vs-Ve)}} f'

In this case, Vs=Ve, f=infinite?
 
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Theoretically, yes. When the emitter travels at the speed of sound, the emitted waves travel along with the emitter and therefore the wavelength will go to zero. So f = Vs/wavelength goes to infinity. That's why you here a blast when a jet reaches sound speed.
 
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Timbuqtu said:
Theoretically, yes. When the emitter travels at the speed of sound, the emitted waves travel along with the emitter and therefore the wavelength will go to zero. So f = Vs/wavelength goes to infinity. That's why you here a blast when a jet reaches sound speed.

Where can i find the demonstration of doppler formula?
 
There's an elegant proof for the Doppler-Fizeau formula in electrodynamics books.I'm sure that setting "c"----"v_{sound}" & making approximations u can find the nonrelativistic cases...All 4 of them (in the case of leght,there are only 2).

Daniel.
 
dextercioby said:
There's an elegant proof for the Doppler-Fizeau formula in electrodynamics books.I'm sure that setting "c"----"v_{sound}" & making approximations u can find the nonrelativistic cases...All 4 of them (in the case of leght,there are only 2).

Daniel.

Dear Dextercious:

I don't understand this "I'm sure that setting "c"----"v_{sound}" & making approximations".

Setting where?
 
In the general Doppler-Fizeau formula...

Daniel.
 
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