If two coherent sources are infinitely close to each other, do you expect an interference pattern ?

Yes. We can always expect to obtain an interference pattern. Yes, depending on the wavelength of light, we may receive interference pattern. No. Due to large fringe width, the interference pattern is not obtained. No. Due to miniscule fringe width, the interference pattern is not obtained.

No. Due to large fringe width, the interference pattern is not obtained.

Fringe width : \(\beta\) ∝ \(\frac{1}{d}\) if d → 0, \(\beta\) → \(\infty\)