No. Don't confuse this with a comparison between a stationary source and a moving source. In that case, the observed frequency with a moving source will be higher than for a stationary source. The point they are making here is that the observed frequency doesn't change as the source approaches (until it passes you).Shouldnt it be that as the point source approaches you the intensity AND frequency increase? (see the pitfall prevention)
No, I think you're still missing the point of that "pitfall prevention" tip.ok i think i see where i made the mistake:
For a stationary source:
as the observer moves toward the source with velocity v, the the frequency obsered would increase as well as the intesity.
as the observer moves away, the frequency would decrease as well as intensity.
The same points made above would apply here. If the source approaches you, then the observed frequency will be higher than the source frequency. But it doesn't change as the source gets closer.for a stationary observer:
as the source moves toward the observer frequency is the same but intensity increases
(and observed wavelength decreses)
if the source moves away, the observe frequency, intensity, and wave length would decrease.