MgCl2 in the molten state is-
1. p-type semiconductor
2. n-type semiconductor
3. Electrolytic conductors
4. Electronic conductors
Cubic close packing in three dimensions is
1. Triangular voids
2. Pattern of spheres is repeated in every fourth layer
3. Coordination number =4
4. Pattern of sphere is repeated in alternate layers
Number of octahedral voids are present per unit cell in a cubic close packed structure :
1. 4
2. 8
3. 6
4. 2
Number of tetrahedral voids voids are present per unit cell in a cubic close packed structure :
1. 4
2. 8
3. 6
4. 2
Doping affects the property of semiconductors. It -
1. Increases the conductivity of semiconductors.
2. Decreases the conductivity of semiconductors.
3. No effect on conductivity of semiconductors.
4. None of the above.
Non-stoichiometric defect present in the sample of ferrous oxide with formula Fe0.93O1.00 -
1. Metal deficiency defect
2. Metal excess defect
3. Frenkel defect
4. Schottky defect
Select the correct option based on statements below:
Assertion (A): | The stability of a crystal is reflected by the magnitude of its melting point. |
Reason (R): | Greater the intermolecular forces of attraction, the higher will be the stability and melting point of the substance. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |
The packing efficiency of the face-centered cubic unit cell is:
(assuming that the atoms are touching each other)
1. 52.40 %
2. 68.04 %
3. 74 %
4. 79.06 %
Silver crystallizes in fcc lattice. If the edge length of the cell is 4.07 × 10−8 cm and density is 10.5 g cm−3, the atomic mass of silver is -
1. 120.31 g
2. 107.9 g
3. 207.60 g
4. 138.52 g
Copper crystallizes into an fcc lattice with an edge length of 3.61 × 10−8 cm. The density of copper crystal will be -
1. 7.46 g cm-3
2. 9.67 g cm-3
3. 8.96 g cm-3
4. 5.63 g cm-3