Silicon doped with electron rich impurity forms -
1. p-type semiconductor.
2. n-type semiconductor.
3. Intrinsic semiconductor.
4. Insulator.
The incorrect statement among the following is:
1. | Paramagnetic substances are weakly attracted by magnetic field. |
2. | Ferromagnetic substances cannot be magnetised permanently. |
3. | The domains in antiferromagnetic substances are oppositely oriented with respect to each other. |
4. | Pairing of electrons cancels their magnetic moment in the diamagnetic substances. |
A ferromagnetic substance becomes a permanent magnet when it is placed in a magnetic field because:
1. | All the domains get oriented in the direction of the magnetic field. |
2. | All the domains get oriented in the direction opposite to the direction of the magnetic field. |
3. | Domains get oriented randomly. |
4. | Domains are not affected by the magnetic field. |
The correct order of the packing efficiency in different types of unit cells is-
1. Fcc < Bcc < Simple cubic
2. Fcc > Bcc > Simple cubic
3. Fcc < Bcc > Simple cubic
4. Bcc < Fcc > Simple cubic
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 |