The Doppler shift can be observed when . Check all that apply. Group of answer choices the source of sound moves towards an observer the source of sound moves away from an observer an observer moves towards a stationary sound source an observer moves away from a stationary sound source the observer and sound source move at the same speed in the same direction the observer and sound source move at the same speed towards one another none of these

the source of sound moves towards an observe

Explanation:

The Doppler effect is related to waves such as sound or light. the effect causes an increase or decrease in the frequency of sound light or other waves when the souces either move towards or away from the observer. For example the siren of the train to a person on the platform, the redshift seen by astronomers.

Therefore, The Doppler shift can be observed when the source of sound moves towards an observer From a place closer to the observer than the last wave's crest, each consecutive wave crest is sent. Each wave therefore, takes a little less time than the preceding wave to reach the observer.

temp rises, and expansion