Coherent Sources — MCQ Practice

Which of the following conditions is NOT essential for two light sources to be considered coherent?

If two light sources are perfectly monochromatic but still do not produce a stable interference pattern, what is the most likely reason?

In Young's Double Slit Experiment (YDSE), why is a single narrow slit used to illuminate the two main slits ($S_1$ and $S_2$)?

Which of the following light sources is generally considered to have the highest degree of coherence?

If two coherent sources are used in an interference experiment and their phase difference is constant at $pi$ radians, what type of interference will occur at points where the path difference is an integral multiple of the wavelength?

Which of the following statements about coherence length is correct?