According to the doppler effect what appears to happen when a light source moves closer to an observer

When the distance between the source and the observer is DEcreasing, the observer sees light that has a shorter wavelength than the light actually had when it left the source.

It doesn't matter how the distance between them is decreasing.  The source could be moving toward the observer, the observer could be moving toward the source, or they could both be moving in a way that makes the separation between them decrease as time goes on.  The result is the same.

(When this is used in Astronomy and Astrophysics, the big trick is:  How does the observer know what the wavelength actually WAS when the light left the source ?)

you go to your settings preference and in the end youll see sth that says "i want to delete my acc" click on it and u'll acc will be deleted but u have to wait.

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.