Dislocation defect is also known as-
1. Frenkel defect.
2. Schottky defect.
3. Non-stoichiometric defect.
4. Simple interstitial defect.
The edge lengths of the unit cells in terms of the radius of spheres constituting fcc, bcc, and simple cubic unit cells are respectively -
1.
2.
3.
4.
Correct statement among the following regarding conductivity in solids is -
1.
2.
3.
4.
Consider the following statements about semiconductors.
I. | Silicon doped with electron-rich impurity is a p-type semiconductor. |
II. | Silicon doped with an electron-rich impurity is an n-type semiconductor. |
III. | Delocalised electrons increase the conductivity of doped silicon. |
IV. | An electron vacancy increases the conductivity of n-type semiconductor. |
1. I and II
2. II and III
3. III and IV
4. I and IV
Match the defects given in Column I with the statements given in Column II.
Column I | Column II |
A. Simple vacancy defect | 1. Shown by non-ionic solids and increases the density of the solid |
B. Simple interstitial defect | 2. Shown by ionic solids and decreases the density of the solid |
C. Frenkel defect | 3. Shown by non-ionic solids and decreases the density of the solid |
D. Schottky defect | 4. Shown by ionic solids and density of the solid remains the same |
Codes
A | B | C | D | |
1. | 3 | 1 | 4 | 2 |
2. | 1 | 2 | 3 | 4 |
3. | 1 | 4 | 3 | 2 |
4. | 4 | 1 | 3 | 2 |
Match the types of defects given in Column I with the statement given in Column II.
Column I | Column II |
A. Impurity defect | 1. NaCl with anionic sites called F-centres |
B. Metal excess defect | 2. FeO with Fe3+ |
C. Metal deficiency defect | 3. NaCl with Sr2+ and some cationic sites vacant |
Codes
A | B | C | |
1. | 2 | 3 | 1 |
2. | 3 | 1 | 2 |
3 | 1 | 2 | 3 |
4. | 2 | 1 | 3 |
Match the items given in Column I with the items given in Column II.
Column I | Column II |
A. Mg in solid state | 1. p-type semiconductor |
B. MgCl2 in molten state | 2. n-type semiconductor |
C. Silicon with phosphorus | 3. Electrolytic conductors |
D. Germanium with boron | 4. Electronic conductors |
Codes
A | B | C | D | |
1. | 2 | 3 | 4 | 1 |
2. | 1 | 2 | 3 | 4 |
3. | 1 | 4 | 3 | 2 |
4. | 4 | 3 | 2 | 1 |
Match the type of packing given in Column I with the items given in Column II.
Column I | Column II |
A. Square close packing in two dimensions | 1. Triangular voids |
B. Hexagonal close packing in two dimensions | 2. Pattern of spheres is repeated in every fourth layer |
C. Hexagonal close packing in three dimensions | 3. Coordination number = 4 |
D. Cubic close packing in three dimensions | 4. Pattern of sphere is repeated in alternate layers |
Codes
A | B | C | D | |
1. | 3 | 2 | 4 | 1 |
2. | 1 | 2 | 3 | 4 |
3. | 3 | 1 | 4 | 2 |
4. | 4 | 1 | 3 | 2 |
Assertion (A): | The total number of atoms present in a simple cubic unit cell is one. |
Reason (R): | Simple cubic unit cell has atoms at its corners, each of which is shared between eight adjacent unit cells. |
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. | (A) is false but (R) is true. |
Select the correct option based on statements below:
Assertion (A): | Graphite is a good conductor of electricity. However, diamond belongs to the category of insulators. |
Reason (R): | Graphite is soft in nature whereas diamond is very hard and brittle. |
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. | (A) is false but (R) is true. |