A Young's double-slit experiment is illuminated with white light under symmetric normal incidence. What is observed exactly at the geometrical centre of the screen?
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Question

A Young's double-slit experiment is illuminated with white light under symmetric normal incidence. What is observed exactly at the geometrical centre of the screen?

G1 Physics · Accepted Answer

At the geometrical centre, Δ = 0. Every wavelength in white light therefore satisfies the constructive-interference condition simultaneously. All visible colours overlap. Hence the central maximum is white. Correct option: C.