Multiple Choice Questions and Answers on Semiconductor Theory

Q11. A pentavalent impurity has ………. Valence electrons

1. 3
2. 5
3. 4
4. 6

Answer : 2

A12. An n-type semiconductor is ………

1. Positively charged
2. Negatively charged
3. Electrically neutral
4. None of the above

Answer : 3

Q13. A trivalent impurity has ….. valence electrons

1. 4
2. 5
3. 6
4. 3

Answer : 4

A14. Addition of trivalent impurity to a semiconductor creates many ……..

1. Holes
2. Free electrons
3. Valence electrons
4. Bound electrons

Answer : 1

Q15. A hole in a semiconductor is defined as …………….

1. A free electron
2. The incomplete part of an electron pair bond
3. A free proton
4. A free neutron

Answer : 2

Q16. The impurity level in an extrinsic semiconductor is about ….. of pure semiconductor.

1. 10 atoms for 10⁸ atoms
2. 1 atom for 10⁸ atoms
3. 1 atom for 10⁴ atoms
4. 1 atom for 100 atoms

Answer : 2

Q17. As the doping to a pure semiconductor increases, the bulk resistance of the semiconductor ………..

1. Remains the same
2. Increases
3. Decreases
4. None of the above

Answer : 3

Q18. A hole and electron in close proximity would tend to ……….

1. Repel each other
2. Attract each other
3. Have no effect on each other
4. None of the above

Answer : 2

Q19. In a semiconductor, current conduction is due to ……..

1. Only holes
2. Only free electrons
3. Holes and free electrons
4. None of the above

Answer : 3

Q20. The random motion of holes and free electrons due to thermal agitation is called ……….

1. Diffusion
2. Pressure
3. Ionisation
4. None of the above

Answer : 1