26. A diffraction data of a cubic crystal of an unknown element show peaks at 2h
angles 38.60°, 55.71°, 69.70°, 82.55°, 95.00° and 107.67°. If the wavelength of
X-ray used is 1.543 Å, identify the element:
(a) Iron
(b) Niobium
(c) Copper
(d) Nickel
27. Bragg’s reflection is observed at an angle of 5° in a transmission Laue pattern
for KCl crystal. If the crystal to film distance is 4 cm, the location of the spot
with reference to center of the film is:
(a) 0.505 cm
(b) 0.605 cm
(c) 0.705 cm
(d) 0.805 cm
28. From a Laue photograph of an fcc crystal, the cell parameter is found to be 4.50
Å. If the potential difference across the X-ray tube is 50 kV and the crystal to
film distance is 5 cm, the minimum distance from the center of the pattern at
which reflection can occur from the plane of maximum spacing is:
(a) 0.78 cm
(b) 0.68 cm
(c) 0.58 cm
(d) 0.48 cm
29. A transmission Laue pattern of a copper crystal with a = 3.62 Å is obtained on
a film kept at a distance of 5 cm. The (100) planes of the crystal make an angle
of 5° with the incident beam. The minimum tube voltage required to produce a
200 reflection is found to be:
(a) 38.82 kV
(b) 48.82 kV
(c) 58.82 kV
(d) 68.82 kV
30. A transmission Laue pattern of a copper crystal with a = 3.62 Å is obtained on
a film kept at a distance of 5 cm. The (100) planes of the crystal make an angle
of 5° with the incident beam. Location of the spot with reference to center of
the film is:
(a) 0.98 cm
(b) 0.88 cm
(c) 0.78 cm
(d) 0.68 cm
9.1 Steps in Crystal Structure Determinations
375
angles 38.60°, 55.71°, 69.70°, 82.55°, 95.00° and 107.67°. If the wavelength of
X-ray used is 1.543 Å, identify the element:
(a) Iron
(b) Niobium
(c) Copper
(d) Nickel
27. Bragg’s reflection is observed at an angle of 5° in a transmission Laue pattern
for KCl crystal. If the crystal to film distance is 4 cm, the location of the spot
with reference to center of the film is:
(a) 0.505 cm
(b) 0.605 cm
(c) 0.705 cm
(d) 0.805 cm
28. From a Laue photograph of an fcc crystal, the cell parameter is found to be 4.50
Å. If the potential difference across the X-ray tube is 50 kV and the crystal to
film distance is 5 cm, the minimum distance from the center of the pattern at
which reflection can occur from the plane of maximum spacing is:
(a) 0.78 cm
(b) 0.68 cm
(c) 0.58 cm
(d) 0.48 cm
29. A transmission Laue pattern of a copper crystal with a = 3.62 Å is obtained on
a film kept at a distance of 5 cm. The (100) planes of the crystal make an angle
of 5° with the incident beam. The minimum tube voltage required to produce a
200 reflection is found to be:
(a) 38.82 kV
(b) 48.82 kV
(c) 58.82 kV
(d) 68.82 kV
30. A transmission Laue pattern of a copper crystal with a = 3.62 Å is obtained on
a film kept at a distance of 5 cm. The (100) planes of the crystal make an angle
of 5° with the incident beam. Location of the spot with reference to center of
the film is:
(a) 0.98 cm
(b) 0.88 cm
(c) 0.78 cm
(d) 0.68 cm
9.1 Steps in Crystal Structure Determinations
375