試題詳解

3. X rays of wavelength λ= 0.250 nm are incident on the face of a crystal at angle θ, measured from the crystal surface. The smallest angle that yields an intense reflected beam is θ = 14.5°. Which of the following gives the value of the interplanar spacing d? ( sin 14.5° 1/4 )
(A)0.125 nm
(B) 0.250 nm
(C) 0.500 nm
(D) 0.625 nm
(E) 0.750 nm