The number of close neighbours in a body centered cubic lattice of identical sphere is
6
4
12
8
Which covalent network crystal is an exception in electrical conductivity?
silicon carbide
diamond
graphite
none of these
________________ is the property of a material by which it allows the flow if electric current.
Resistivity
Conductivity
Superconductivity
Sublimation
The defect which is caused if some of the lattice points are unoccupied are called
Point defect
Lattice vacancies
Schottky defect
Frenkel defect
Which of the following allows light to pass through it?
coal
lead
Which of the following is transparent?
Which of the following has its atoms connected by valence bonds?
sodium chloride
none of the above
________________ is a good example of covalent crystal .
Diamond
Ice
Graphite
Charcoal
Which crystal vapourize at 7000oC?
Which of the following has 1.54 Ao bond length throughout the crystal?
