PrepBharat

1. Crystals can be classified into basic crystal habits, equal to
a) 7
b) 4
c) 14
d) 2

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2. Tetragonal crystal system has the following unit cell dimensions
a) \[a = b = c, \alpha = \beta = \gamma = 90°\]
b) \[a = b \neq c, \alpha = \beta = \gamma = 90°\]
c) \[a\neq b \neq c, \alpha = \beta = \gamma = 90°\]
d) \[a = b \neq c, \alpha = \beta = 90° \gamma = 120°\]

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3. A match box exhibits
a) cubic geometry
b) monoclinic geometry
c) tetragonal geometry
d) orthorhombic geometry

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4. When molten zinc is cooled to solid state, it assumes hcp structure. Then the number of nearest neighbours of zinc atom will be
a) 4
b) 6
c) 8
d) 12

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5. Co-ordination number of \[Na^{+}\] in NaCl is
a) 4
b) 3
c) 6
d) 5

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6. A crystal lattice with alternate +ve and –ve ions has radius ratio 0.524. Its co-ordination number is
a) 4
b) 3
c) 6
d) 12

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7. How many unit cells are present in a cube-shaped ideal crystal of NaCl of mass 1.00 g? [Atomic masses : Na = 23, Cl = 35.5]
a) \[2.57 × 10^{21}\]   unit cells
b) \[5.14 × 10^{21}\]   unit cells
c) \[1.28 × 10^{21}\]   unit cells
d) \[1.71 × 10^{21}\]   unit cells

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8. Which of the following is example of body centred cube ?
a) Mg
b) Zinc
c) Copper
d) Sodium

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9. Which of the following describes the hexagonal close packed arrangement of spheres?
a) ABCABA
b) ABCABC
c) ABABA
d) ABBABB

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10. A metallic crystal crystallizes into a lattice containing a sequence of layers AB AB AB......Any packing of spheres leaves out voids in the lattice. What percentage of volume of this lattice is empty space?
a) 74%
b) 26%
c) 50%
d) none of these

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