When X-rays of wavelength λ = 0.2 nm are reected o the face of a crystal, a Bragg maximum is observed at a glancing angle of θ = 17.5 o , with sucient intensity that it is judged to be rst order. (a) What is the spacing d between the crystal planes that are parallel to the face in question? (b) What are the glancing angles of all higher order maxima?

finding spacing between crystal planes

2dsin∅ =  λ

d = λn/ 2sin∅

d = 0.2nm/2sin17.5

∴ d = 0.333 nm

Nmax ×λ = 2d

n = 2×0.333/0.2

n = 3

∴ 2dsin∅ = λ×n

sin∅ = 0.2nm×3/2×0.333nm

sin∅ =0.90

∅ = 64°

Explanation:

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