683.

Problem 47.31 (RHK)

A beam of x rays of wavelength 29.3 pm is incident on a calcite crystal of lattice spacing 0.313 nm. We have to find the smallest angle between the crystal planes and the beam that will result in constructive reflection of the x rays.

Solution: Click For PDF Version

where d is the lattice spacing.

It is given that

,

and

Therefore, the smallest angle between the crystal planes and the beam that will result in constructive interference will be