A superconductor has a lattice spacing of . What is the angle of incidence (in degrees) for X-rays of wavelength
. that undergo a first-order diffraction from the crystal surface, according to Bragg's equation?
Bragg's equation relates the wavelength of X-rays to the angle of incidence and the lattice spacing of a crystal:
where d is the lattice spacing, is the angle of incidence, n is the order of diffraction, and
is the wavelength of the incident X-rays.
For a first-order diffraction (n = 1) from a superconductor with a lattice spacing of and X-rays of wavelength
,Bragg's equation becomes:
Simplifying and solving for ,we get
Hence, option b) 31.4° is the correct answer.