試題詳解

47. Coherent light with wavelength 0.40 μm passes through two very narrow slits. The distance between these two slits is 0.20 mm. The interference pattern is shown on a screen 5.0 m from the slits. What is the width of the central interference maximum?
(A) 7.5 mm
(B) 5.0 mm
(C) 20 mm
(D) 10 mm
(E) 2.5 mm