Silicon gives p-type of semiconductor on doping with:
1. Germanium.
2. Arsenic.
3. Selenium.
4. Boron.
For a cubic crystal structure, which one of the following relations indicating the cell characteristic is correct?
1.
2.
3.
4.
CsBr crystallises in a body-centered cubic lattice. The unit cell length is 436.6 pm. Given that the atomic mass of Cs = 133 amu and that of Br = 80 amu and the Avogadro number being 6.02×1023 mol-1, the density of CsBr is:
1. 42.5
2. 0.425
3. 8.25
4. 4.25
A compound is formed by cation C and anion A. The anions form hexagonal close packed (hcp) lattice and the cations occupy 75 % of octahedral voids. The formula of the compound is:
1.
2.
3.
4.
Ionic radii of Mg2+ and O2- ions are 66 pm and 140 pm respectively. The type of interstitial void and coordination number of Mg2+ ion respectively are
1. Tetrahedral, 12
2. Octahedral, 6
3. Tetrahedral, 6
4. Octahedral, 8
An element crystallizes in a structure having FCC unit cell of an edge length 200 pm. If
200 g this element contains 24 x 1023 atoms, the density of the element is
1. 50.3 g/cc
2. 63.4 g/cc
3. 41.6 g/cc
4. 34.8 g/cc
If the lattice parameter for a crystalline structure is 3.6 Å, then the atomic radius in fcc crystal is:
1. 1.81 Å
2. 2.10 Å
3. 2.92 Å
4. 1.27 Å
The number of octahedral void(s) per atom present in a cubic close-packed structure is:
1. 1
2. 3
3. 2
4. 4