試題詳解

24. Consider a soap film of thickness t and index of refraction n (＞1) suspending in air (index of refraction ~1). Light of wavelength λ is incident on the soap normally. If the intensity of the reflection is 0 (destructive completely), what is the maximum of 2t?
(A) nt
(B) 2t
(C) 2nt
(D) 4t
(E) 4nt