Question

7. First-order diffraction peak of (310) planes occurs at a diffraction angle of 46.21° for BCC iron when monochromatic radiation having a wavelength Calculate the density of the material (Atomic mass of iron is 55.85 g/mol).

Answer 1

. This C Th: пил hion can bе аѕ wе угі (Aina B«Моти) of diffraction; na = 2dsino in order of diffraction. d= interplanar distance n = wave-length of radiation des o: angle of diffraction diffraction; n = 1. since it is 1st order a = 0.091910-9 m 046.21 1 X 0.071 X 10*1 = 2 x d x sin.46.21 or d = 3.55 x 10 all sin 46.21 or d = u. U8 x 10-11 m or d = 49.8 pm 1:1 pm = 10-12 m 7 Now, if Ih, k, d) be the merrey indices of a crystals then the edge-length lal and d' me related asi da Miller For Bec iron, (h, k, 1) = (3,2,0) adx V139703 760)* or as 44.8 x V 10 pm a £ 141.46 pm or a. 14.768 10-12 m a 1.42 Ă In 2100 Now; density of a crystal is given by : - NA. Aumgandro number M: atomic mass MM n = no of whith atoms in NAA² unit - cell - edge-length

call convert gmolt so, we shall given in sity is Now, the density is given cgis unit for a a. 146 10"? m in t a - for Bcc lattice, n = 20 for Bo - 141.20 x 10-10 cm = 1.4176 x 10-8 cm. . $ 2 x 55.85 6.023 x 1023 *1.4176X10 85.09 gee! P