11. The first three S-values obtained from the powder pattern of a given unknown
cubic form material are 24.95, 40.9 and 48.05 mm, respectively. If the radius of
the camera is 57.3 mm and Molybdenum K a radiation of wavelength 0.71 Å is
used. Determine the crystal structure of the cubic form and its lattice parameter:
(a) SC
(b) BCC
(c) FCC
(d) DC
12. In an X-ray diffraction experiment, the first reflection from an fcc crystal is
observed at 2h ¼ 84
when CuKa radiation of wavelength 1.54 Å is used. The
indices of possible reflections are:
(a) (111), (200)
(b) (200), (220)
(c) (111), (220)
(d) (200), (311)
13. In an X-ray diffraction experiment, the first reflection from an fcc crystal is
observed at 2h ¼ 84
when CuKa radiation of wavelength 1.54 Å is used. The
values of interplanar spacing corresponding to possible reflections are:
(a) 0.15 Å, 0.88 Å
(b) 1.15 Å, 0.99 Å
(c) 2.15 Å, 1.88 Å
(d) 3.15 Å, 1.99 Å
14. A powder pattern is obtained for an fcc crystal with lattice parameter 3:52 ˚
A by
using X-ray of wavelength 1:79 ˚
A: The lowest reflection possible is:
(a) (200)
(b) (400)
(c) (111)
(d) (222)
15. A powder pattern is obtained for an fcc crystal with lattice parameter 3:52 ˚
A by
using X-ray of wavelength 1:79 ˚
A. The highest reflection possible is:
(a) (200)
(b) (400)
(c) (111)
(d) (222)
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9 Determination of Crystal Structure Parameters