Due to interference, a thin film reflects no orange light...it appears dark. If you double its thickness and illuminate it again with orange light, what will you see? Choose one answer only.

It will appear dark again.
It will appear bright (strongly reflecting the orange light).
It could be either bright or dark, depending on the film.

2 answers

no knowing whether a phase shift has occurred at both or just one boundary, it could be bright or dark.
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