Question

A crystal is irradiated with x-rays with a wavelength of 0.120 nm. the atomic planes in the crystal are separated by 0.21 nm. at what angles of incidence with respect to the normal will the x-rays reflect from the crystal?

Answer 1

The angles of incidence with respect to the normal will the x-rays reflect from the crystal will be 16.60 degrees. 

Given: wavelength of X-rays, λ= 0.120 nm

Distance, d=0.21 nm

According to Bragg’s diffraction law: nλ = 2dsinθ

thus, 0.120 = 2*0.21sinθ

or θ = $sin^{-1}$ (0.120/2*0.21)

or θ = 16.60 degrees.