Two light sources are said to be coherent if they
A. are of the same frequency.
B. are of the same frequency, and maintain a constant phase difference.
C. are of the same amplitude, and maintain a constant phase difference.
D. are of the same frequency and amplitude.
Answer:B
Two light sources are said to be coherent if they
A. are of the same frequency. B. are of the same frequency, and maintain a constant phase difference. C. are of the same amplitude, and maintain a constant phase difference. D. are of the same frequency and amplitude.