The spacing between layers of molybdenum atoms is 157 pm. calculate the angle in which 154 pm x-rays produces a maximum reflection for n = 1.

Answer : The correct answer is : 29.34 °

The spacing between layers , incident angle and wavelength is described by Bragg's Law which states :

nλ = 2d sin∅

Where , n = an inetger

λ = wavelength of the x-ray

d = spacing of crystal layers ( path difference )

∅ = is incident angle

Given : = d = 157 pm λ= 154 pm n=1

Plugging values in formula => 1 * 154 pm = 2 * 157 pm * sin∅

154 pm = 314 pm * sin∅

Dividing 314 pm on both side .

154 pm/ 314pm = 314pm/314pm * sin∅

0.490 = sin∅

∅ = sin^-1 0.490

∅= 29.34 °

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