1. When the atoms are separated by equilibrium distance of r o, then the resultant force between atoms at ro is

(a) Zero

(b) Negative

(c) Maximum

(d) Positive

2. Pure and dry ionic solids are

(a) Superconductors

(b) Semi-conductors

(c) Good conductors

(d) Insulators

3. At equilibrium condition a diatomic molecule possesses

(a) Minimum potential energy

(b) zero potential energy

(c) Maximum energy

(d) Maximum potential energy

4. Total number of basic crystal systems, is

(a) 8

(b) 14

(c) 7

(d) 6

5. If a = b = c, α = β = γ  = 90o the crystal is

(a) Tetragonal

(b) Triclinic

(c) Cubic

(d) Orthorhombic

6. There are four Bravais lattices for the crystal system of 

(a) Cubic

(b) Monoclinic

(c) Hexagonal

(d) Orthorhombic

7. The packing factor is defined as the ratio of 

(a) the volume of the unit cell to the volume of all the atoms

(b) the volume of all atoms in the unit cell to the volume of the unit cell

(c) the number of all atoms in the unit cell to the volume of the unit cell

(d) the volume of the unit cell to the number of atoms

8. If r is the radius of the atom in a crystal of simple cubic structure, then the nearest neighbour distance is

(a) 2r

(b) 4r

(c) 3r

(d) r/2

9. If ‘a’ is the side of a BCC cell, then the nearest neighbour distance is

(a) a

(b) a√

2

(c) a√

2

(d) a√

3

2

10. Highly close packed structure is

(a) FCC

(b) BCC

(c) Polinium

(d) SC

11. The coordination number of Germanium is

(a) 6

(b) 4

(c) 12

(d) 8

12. The Bravais lattice of ZnS is

(a) hexagonal close packed

(b) body centered cubic

(c) simple cubic

(d) face centered cubic

13. If ro is the equilibrium spacing, the potential energy (V) of NaCl molecule is given by the relation

(a) V  = e2/4πεor2o

(b) V  = −e2/4πεoro

(c) V  = −e/4πεoro

(d) V  = e/4πεoro

14. The coordinates of chlorine ion in CsCl structure are

(a) 1/2, 1/2, 1/2

(b) 1, 1, 1

(c) 0, 0, 1

(d) 2, 2, 2

15. In a cubic crystal a plane makes intercepts 1, -4, ∞ on the x,y,z axes respectively. The Miller indices of the planeare

(a) (4, 0, 1)

(b) (4 , 0, 1 )

(c) (4,0, 1)

(d) (4, 1 , 0)

16. The direction opposite to [102] is

(a) [2 0 1]

(b) [2 0 4]

(c) [2 0 1]

(d) [1 0 2]

17. The interplanar separation (d) in tetragonal crystal is

(a) d = 1 

h2+k2

a2+

l2

c2

(b) d = 1 

h2+k2+l2

a2

(c) d = 1 

h2

a2+

k2l2

c2

(d) d = 1 

h2

a2+

k2

b2+

l2

c2

18. If the path difference between the X-rays reflectd by successive crystal planes is n λ where n=1,2,3 ............ thenthe intensity of each diffracted ray is

(a) negative

(b) maximum

(c) minimum

(d) zero

19. X-rays of wavelength 1.54 A.U. are diffracted by a crystal with the first maximum occurring at 12 o. What is theseparation between the lattice planes?

(d) 3.203 A.U.

20. X-ray powder method is usually carried for

(a) any material

(b) crystalline materials

(c) polycrystalline materials

(d) amorphous materials