The cubic unit cell of a metal (molar mass = 63.55g mol-1) has an edge length of 362 pm. Its density is 8.92g cm-3. The type of unit cell is
primitive
face centred
body centred
end centred
The number of unit cells present in 39 g of potassium if it crystallizes as body centred cube is (N = Avogadro number, At. wt. of potassium = 39)
N
The number of octahedral and tetrahedral holes respectively present in a hexagonal close packed (hcp) crystal of 'X' atoms are
X, 2X
X, X
2X, X
2X, 2X
Which one of the following elements, when present as an impurity in silicon makes it a p-type semiconductor?
As
P
In
Sb
An element has a body centered cubic structure with a unit cell edge length of 400 pm. Atomic mass of an element is 24 g mol-1. What is the ·density of the element? (NA = 6 × 1023 mol-1)
2.50 g cm-3
1.80 g cm-3
3.60 g cm-3
1.25g cm-3
The number of octahedral sites per sphere arranged in a face centred cubic structure, is
1
2
3
4
Which one of the following has Frenkel defect?
sodium chloride
Graphite
Siliver Bromide
Diamond
C.
Siliver Bromide
Frenkel defect is present in those compounds which have low coordination number and large difference in the size of cations and anions.