1. TEST PAPER
The Solid State
One mark questions :
1. What is coordination number of hcp and ccp structures ?
2. State the type of crystal defectshown by AgBr.
3. What is radius ratio (r+
/r-
) for an ion to occupy tetrahedral sites?
4. How many atoms are there in a unit cell of a metal crystallizing in fcc structure?
5. In a trigonal crystal :
(a) a = b = c , α = β = γ ≠ 90o
(b) a = b ≠ c , α = β = γ = 90o
(c) a ≠ b ≠ c , α = β = γ = 90o
(d) a = b ≠ c , α = β = 90o
γ = 120o
Two marks Questions :
6. iron has bcc unit cell edge 286.26 pm.The density of iron is 7.87 gm cm–3
.Use the information to
calculate Avogadro number. (At. Mass of Fe = 56 gm mol–1
)
7. Tungesten crystallizes in a bcc lattice, calculate the number of unit cells in 1.5 gm of tungesten. At.
Mass of Tungesten= 184u.
8. What is Schottky defect? Finf out the packing efficiencyin a simple cubic lattice.
9. Explain the following :
(a) F – centre (b) Doping
10. Answer the following:
(a) Why does Frenkel defectnot change the density of AgCl crystals?
(b) Why does electricalconductivity of a semiconductorincreases with rise in temperature?
