Which effect causes the apparent change in frequency of light from a moving star?
A
Photoelectric effect
B
Compton effect
C
Zeeman effect
D
Doppler effect
Correct Answer: Option D — Doppler effect
Explanation:
The Doppler effect causes light from a star moving away from us to shift to longer wavelengths called red shift while light from an approaching star shifts to shorter wavelengths called blue shift.