A monochromatic light of wavelength \(800 \mathrm{~nm}\) is incident normally on a single slit of width \(0.020 \mathrm{~mm}\) to produce a diffraction pattern on a screen placed \(1 \mathrm{~m}\) away. Estimate the number of fringes obtained in Young's double slit experiment with slit separation \(0.20 \mathrm{~mm}\), which can be accommodated within the range of total angular spread of the central maximum due to single slit.

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.