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