試題詳解

19. Monochromatic light is normally incident on a diffraction grating that has 10000 slits and is 1 cm wide. If the second-order line is deviated at 30 degrees, what is the wavelength of the incident light?
(A) 250 nm
(B) 433 nm
(C) 500 nm
(D) 866 nm
(E) 1000 nm