🧪 Semiconductor MCQ Quiz Hub

1. A semiconductor is formed by ……… bonds.
Covalent
Electrovalent
Co-ordinate
none of the above

2. A semiconductor has ………… temperature coefficient of resistance.
Positive
Zero
Negative
none of the above

3. The most commonly used semiconductor is ………..
Germanium
Silicon
Carbon
Sulphur

4. A semiconductor has generally ……………… valence electrons.
2
3
6
4

5. The resistivity of pure germanium under standard conditions is about ……
Ω cm
60
Ω cm
3 x 106

6. The resistivity of a pure silicon is about ……
100 Ω cm
6000 Ω cm
3 x 105 Ω m
6 x 10-8 Ω cm

7. When a pure semiconductor is heated, its resistance ……
Goes up
Goes down
Remains the same
Can’t say

8. The strength of a semiconductor crystal comes from ……
Forces between nuclei
Forces between protons
Electron-pair bonds
none of the above

9. When a pentavalent impurity is added to a pure semiconductor, it becomes …
An insulator
An intrinsic semiconductor
p-type semiconductor
n-type semiconductor

10. Addition of pentavalent impurity to a semiconductor creates many ……
Free electrons
Holes
Valence electrons
Bound electrons

11. A pentavalent impurity has ………. Valence electrons
3
5
4
6

12. An n-type semiconductor is ………
Positively charged
Negatively charged
Electrically neutral
none of the above

13. A trivalent impurity has ….. valence electrons
4
5
6
3

14. Addition of trivalent impurity to a semiconductor creates many ……..
Holes
Free electrons
Valence electrons
Bound electrons

15. A hole in a semiconductor is defined as ………
A free electron
The incomplete part of an electron pair bond
A free proton
A free neutron

16. The impurity level in an extrinsic semiconductor is about ….. of pure semiconductor.
10 atoms for 108 atoms
1 atom for 108 atoms
1 atom for 104 atoms
1 atom for 100 atoms

17. As the doping to a pure semiconductor increases, the bulk resistance of the semiconductor ……
Remains the same
Increases
Decreases
none of the above

18. A hole and electron in close proximity would tend to ……
Repel each other
Attract each other
Have no effect on each other
none of the above

19. In a semiconductor, current conduction is due to ……..
Only holes
Only free electrons
Holes and free electrons
none of the above

20. The random motion of holes and free electrons due to thermal agitation is called ……
Diffusion
Pressure
Ionisation
none of the above

21. A forward biased pn junction diode has a resistance of the order of
Ω
kΩ
MΩ
none of the above

22. The battery connections required to forward bias a pn junction are ……
+ve terminal to p and –ve terminal to n
-ve terminal to p and +ve terminal to n
-ve terminal to p and –ve terminal to n
none of the above

23. The barrier voltage at a pn junction for germanium is about ………
5 V
3 V
Zero
3 V

24. In the depletion region of a pn junction, there is a shortage of ……..
Acceptor ions
Holes and electrons
Donor ions
none of the above

25. A reverse bias pn junction has ……
A reverse bias pn junction has ……
Almost no current
Very low resistance
Large current flow

26. A pn junction acts as a ………
Controlled switch
Bidirectional switch
Unidirectional switch
none of the above

27. A reverse biased pn junction has resistance of the order of
Ω
kΩ
MΩ
none of the above

28. The leakage current across a pn junction is due to ……
Minority carriers
Majority carriers
Junction capacitance
none of the above

29. When the temperature of an extrinsic semiconductor is increased, the pronounced effect is on……
Junction capacitance
Minority carriers
Majority carriers
none of the above

30. With forward bias to a pn junction , the width of depletion layer ………
Decreases
Increases
Remains the same
none of the above

31. The leakage current in a pn junction is of the order of
Aa
mA
kA
µA

32. In an intrinsic semiconductor, the number of free electrons ………
Equals the number of holes
Is greater than the number of holes
Is less than the number of holes
none of the above

33. At room temperature, an intrinsic semiconductor has ……….
Many holes only
A few free electrons and holes
Many free electrons only
No holes or free electrons

34. At absolute temperature, an intrinsic semiconductor has ……….
A few free electrons
Many holes
Many free electrons
No holes or free electrons

35. At room temperature, an intrinsic silicon crystal acts approximately as …
A battery
A conductor
An insulator
A piece of copper wire

36. Under normal conditions a diode conducts current when it is ……
reverse biased
forward biased
avalanched
saturated

37. The term bias in electronics usually means ……….
the value of ac voltage in the signal.
the condition of current through a pn junction.
the value of dc voltages for the device to operate properly.
the status of the diode.

38. Intrinsic semiconductors are those
Which are made of semiconductor material in its purest form
Which have zero energy gap
Which have more electrons than holes
Which are available locally

39. Intrinsic semiconductor at room temperature will have, ................. available for conduction
Electrons
Holes
Both electrons and holes
none of the above

40. A pure semiconductor behaves like an insulator at 00 K because
There is no recombination of electrons with holes
Drift velocity of free electrons is very small
Free electrons are not available for current conduction
Energy possessed by electrons at that low temperature is almost zero

41. Which of the following is a semi-conductor
Diamond
Arsenic
Phosphorous
Gallium arsenide

42. The energy gap is much more in silicon than in germanium because
It has less number of electrons
It has high atomic mass number
Its crystal has much stronger bonds called ionic bonds
Its valence electrons are more tightly bound to their parent nuclii

43. A semiconductor in its purest form is called.......
Insulator
Superconductor
Intrinsic semiconductor
Extrinsic semiconductor

44. A P-type semiconductor results when
A pentavalent impurity is added to an intrinsic semiconductor
A trivalent impurity is added to an intrinsic semiconductor
Either a pentavalent or trivalent impurity is added to an intrinsic semiconductor
none of the above

45. An intrinsic semiconductor at absolute zero.........
Becomes extrinsic semiconductor
Behaves like an insulator
Disintegrates into pieces
Becomes superconductor

46. A semiconductor has.... temperature co-efficient of resistance.
Zero
Positive
Negative
none of the above

47. A doped semiconductor is also known as
Intrinsic semiconductor
Extrinsic semiconductor
Diffused semiconductor
none of the above

48. In semiconductor the forbidden energy gap lies
Just below the conduction band
Just above the conduction band
Either above or below the conduction band
Between the valence band and conduction band

49. Which of the following cannot exist outside a semiconductor
Hole
Electron
Both (a) and (b)
none of the above

50. In a N-type semiconductor, the positive of the Fermi level
Is at the centre of the energy gap
Is lower than the centre of energy gap
Is higher than the centre of energy gap
Can be anywhere depending upon the doping concentration