What is the doppler effect? (2 points) select one: a. the apparent change in frequency of waves due to the motion of a source b. the change in wave speed when it changes mediums c. the electricity created by light waves d. the change in wavelength when visible light strikes a prism

Option A

The apparent change in frequency of waves due to the motion of a source

Explanation:

Doppler effect is the apparent change in frequency of waves due to the motion of a source. Doppler effect occurs when the source of waves moves towards the observer which causes emission of successive wave crests to be closer to the observer compared to the previous wave crest. This phenomenon was named after Austrian Physicist called Christian Doppler