1. Which one of the following is non-crystalline or amorphous?

• (a) Diamond

• (b) Graphite

• (c) Glass

• (d) Common Salt

2. How many chloride ions are surrounding sodium ion in sodium chloride crystal ?

• (a) 4

• (b) 8

• (c) 6

• (d) 12

3. Alkali halides do not show Frenkel defect because

• (a) cations and anions have almost equal size

• (b) there is a large difference in size of cations and anions

• (c) cations and anions have low coordination number

• (d) anions cannot be accommodated in voids

4. Edge length of unit cell of chromium metal is 287 pm with bcc arrangement. The atomic radius is of the order

• (a) 287 pm

• (b) 574 pm

• (c) 124.27 pm

• (d) 143.5 pm

5. The density of a metal which crystallises in bcc lattice with unit cell edge length 300 pm and molar mass 50 g mol-1 will be

• (a) 10 g cm-3

• (b) 14.2 g cm-3

• (c) 6.15 g cm-3

• (d) 9.3 2 g cm-3

Which of the following crystals does not exhibit Frenkel defect?

• (a) AgBr

• (b) AgCl

• (c) KBr

• (d) ZnS

7. What type of stoichiometric defect is shown by ZnS?

• (a) Schottky defect

• (b) Frenkel defect

• (c) Both Frenkel and Schottky defects

• (d) Non-stoichiometric defect

8. What is the effect of Frenkel defect on the density of ionic solids?

• (a) The density of the crystal increases

• (b) The density of the crystal decreases

• (c) The density of the crystal remains unchanged

• (d) There is no relationship between density of a crystal and defect present in it

9. To get n-type of semiconductor, germanium should be doped with

• (a) gallium

• (b) arsenic

• (c) aluminium

• (d) boron

10. p-type semiconductors are formed When Si or Ge are doped with

• (a) group 14 elements

• (b) group 15 elements

• (c) group 13 elements

• (d)group 18 elements