Saved Bookmarks
| 1. |
On transmitting a bem of Xrays with wavelength lambda = 17.8pm through a polycrystalline specimen a system of diffraction rings is producedon a screen located at a distance l = 45 cm fom the specimen. Determine the radius of the bright rind corresponding to second order of reflection from the system of planes with interplanar distance d = 155pm |
|
Answer» SOLUTION :In a polycrysyalline specimen, microcystals are orientyed at various angles with respect to one another. The microcrystals which are oriented at certain special angles with respect to the incident beam produce diffraction MAXIMA that appear as rings. The radiqal of these rings are given by `r = l tan 2 ALPHA` where the Bragg's law gives `2D SIN alpha = k lambda` In our case `k = 2, d = 155pm, lambda = 17.8pm` so `alpha = sin^(-1) .(17.8)/(155) = 6.6^(@)` and `r = 3.52 cm`. 
|
|