Dr. Vikas Yadav
October 27, 2021 at 3:43:32 PM
Quiz – 01
1. In a face cantered cubic lattice, atom (A) occupies the corner positions and atom (B) occupies the face centre positions. If one atom of (B) is missing from one of the face cantered points, the formula of the compound is:
2. Copper has the face centred cubic structure. The coordination number of each ion is:
3. Schottky defect in crystal is observed when:
(a) An ion leaves its normal site and occupies the interstitial site.
(b) Equal number of cations and anions are missing from the lattice.
(c) Unequal number of cations and anions are missing from the lattice.
(d) Density of the crystal is increased.
4. Crystalline solids are anisotropic in nature. What is the meaning of anisotropic in the given statement?
(a) A regular pattern of arrangement of particles which repeats itself periodically over the entire crystal.
(b) Different values of some of physical properties are shown when measured along different directions in the same crystals.
(c) An irregular arrangement of particles over the entire crystal.
(d) Same values of some of physical properties are shown when measured along different directions in the same crystals.
5. Cubic close packing arrangement is also known as:
(a) Hexagonal close packing
(b) Face cantered cubic
(c) Body cantered cubic
(d) None of these
6. An ionic compound is made up of A cations and B anions. If A cations are present at the alternate corners and B anion is present at the diagonal, the formula of the ionic compound will be:
7. Crystals show colour due to the presence of:
(d) None of these
8. Which one of the following is non-crystalline or amorphous?
(d) Common Salt
9. In NaCl structure, Na+ ions occupy:
(a) All octahedral and tetrahedral sites are occupied
(b) Only octahedral sites are occupied
(c) Only tetrahedral sites are occupied
(d) Neither octahedral nor tetrahedral sites are occupied
10. 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
11. 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
12. 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
13. To get n-type of semiconductor, germanium should be doped with:
14. p-type semi-conductors 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
15. Which of the following statement is not true about amorphous solids?
(a) On heating they may become crystalline at certain temperature.
(b) They may become crystalline on keeping for long time.
(c) Amorphous solids can be moulded by heating.
(d) They are anisotropic in nature.
16. Na and Mg crystallise in bcc and fcc structures respectively. The value of Z (number of atoms) for their crystals is:
(a) 8 and 14
(b) 2 and 4
(c) 14 and 8
(d) 6 and 4
17. Which type of defect has the presence of cations in the interstitial sites?
(a) Schottky defect
(b) Vacancy defect
(c) Frenkel defect
(d) Metal deficiency defect
18. The vacant space in body centred cubic lattice unit cell is:
19. A compound formed by elements A and B has a cubic structure in which A atoms are at the corners of cube and B atoms are at the face centres. The formula of the compound will be:
20. A solid is made up of two elements X and Y. Atoms of Y are in ccp arrangement while atoms of X occupy all the tetrahedral sites. The formula of the compound will be: