Doping causes-
1. Dislocation defect.
2. Schottky defect.
3. Frenkel defect.
4. Electronic defect.
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. |
Which of the following is not true about the ionic solids?
1. | Bigger ions form the close packed structure |
2. | Smaller ions occupy either the tetrahedral or‘the octahedral voids depending upon their size |
3. | Occupation of all the voids is not necessary |
4. | The fraction of octahedral or tetrahedral voids occupied depends upon the radii of the ions occupying the voids |
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.
In the cubic close packing, the unit cell has ......... .
1. | 4 tetrahedral voids each of which is shared by four adjacent unit cells. |
2. | 4 tetrahedral voids within the unit cell. |
3. | 8 tetrahedral voids each of which is shared by four adjacent unit cells. |
4. | 8 tetrahedral voids within the unit cells. |
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.