How calculate grain size only with: FWHM and λ?

"We know that a metal have 3 difraction peaks with FWHM of 0.0035°, 0.045° and 0.0055°. Calculate the size grain if we use λ = 1.54 Å". I can't find an answer how to calculate this. The problem...

13 December 2018 1,405 3 View