semiconductor mcqs 200 +
special purpose diodes mcq
Q1.The semiconductor materials have ________
Free electrons
Holes
Both a and b
None of the above
2.By adding pentavalent impurity atoms to an intrinsic semiconductor material, the number of ________ increased
Electrons
Both a and b
None of the above
3.__________ is an example of semiconductor
Capacitors
Op-amps
all
4.The resistivity of the silicon is __________
0.46Ωm
100Ωm
210Ωm
640Ωm
5.How many outer shell valence electrons does silicon have?
One
Two
Three
Four
6.The electrical conductivity of semiconductor lies in ___________
Inductor
Conductor
Both a and b
None of the above
7.The drift current density effected by _______
An electric filed
Concentration gradient in holes
Concentration gradient in free electrons
All of the above
8. For an intrinsic semiconductor material to have more holes, they are doped with ________atoms
Trivalent impurity
Pentavalent impurity
Both a and b
None of the above
9. How many valence electrons do trivalent impurity atoms have in their valence shell?
One
Two
Three
Four
10. The majority charge carriers in N-type semiconductor is __________
Holes
Electrons
Both a and b
None of the above
11. Which one is an insulator example?
Glass
Copper
Phosphorous
None of the above
12. Which one is a donor example?
Boron
Copper
Phosphorous
None of the above
13. The diffusion current density effected by _____
Concentration gradient in the hole
Concentration gradient in free electrons
Both a and b
None of the above
14. The semiconductors doped with trivalent atoms are ________ type of semiconductor
N-type
P-type
Both a and b
None of the above
15. The doping process converts intrinsic semiconductor material into extrinsic semiconductor material
True
False
16. In P-type semiconductor ________ are the majority charge carriers
Electrons
Holes
Both a and b
None of the above
17.A semiconductor is formed by ……… bonds.
Covalent
Electrovalent
Co-ordinate
None of the above
18.A semiconductor has ………… temperature coefficient of resistance.
Positive
Zero
Negative
None of the above
19.The most commonly used semiconductor is ………..
Germanium
Silicon
Carbon
Sulphur
20.A semiconductor has generally ……………… valence electrons.
2
3
6
4
21.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
22.The resistivity of pure germanium under standard conditions is about ……….
6 x 104Ω cm
60Ω cm
3 x 106Ω cm
6 x 10-4Ω cm
23.When a pure semiconductor is heated, its resistance …………..
Goes up
Goes down
Remains the same
Can’t say
24.The strength of a semiconductor crystal comes from ……..
Forces between nuclei
Forces between protons
Electron-pair bonds
None of the above
25.Addition of pentavalent impurity to a semiconductor creates many ……..
Free electrons
Holes
Valence electrons
Bound electrons
26.An n-type semiconductor is ………
Positively charged
Negatively charged
Electrically neutral
None of the above
27.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
28.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
29.In a semiconductor, current conduction is due to ……..
Only holes
Only free electrons
Holes and free electrons
None of the above
30.The random motion of holes and free electrons due to thermal agitation is called ……….
Diffusion
Pressure
Ionisation
None of the above
31.A forward biased p-n junction diode has a resistance of the order of
Ω ohms
kΩ
MΩ
None of the above
32.In the depletion region of a p-n junction, there is a shortage of ……..
Acceptor ions
Holes and electrons
Donor ions
None of the above
33.A reverse bias p-n junction has …………
Very narrow depletion layer
Almost no current
Very low resistance
Large current flow
34.A p-n junction acts as a ……….
Controlled switch
Bidirectional switch
Unidirectional switch
None of the above
35.A reverse biased p-n junction has resistance of the order of
Ω
kΩ
MΩ
None of the above
36.The leakage current across a p-n junction is due to …………..
Minority carriers
Majority carriers
Junction capacitance
None of the above
37.With forward bias to a p-n junction , the width of depletion layer ………
Decreases
Increases
Remains the same
None of the above
38.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
39.At absolute temperature, an intrinsic semiconductor has ……….
A few free electrons
Many holes
Many free electrons
No holes or free electrons
40. Under normal conditions a diode conducts current when it is ……………
reverse biased
forward biased
avalanched
saturated
41.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.
42.The battery connections required to forward bias a p-n 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
43.A reverse bias p-n junction has …………
wide depletion layer
Large current
Very low resistance
Large current flow
44.The resistivity of a semiconductor ____________ conductors and insulators
More than that of
Lies between
Less than that of
None of the above
45.The resistivity of pure silicon is about___________
100 Ω cm
60,000 Ω cm
3 × 106 Ω cm
1.6 × 10−8 Ω cm
46.The relation between the number of free electrons in semiconductor and its temperature is given as
n∝T
n∝T2
n∝T3/2
n∝√T
47.Which of the following does the resistivity of a semiconductor depend upon?
Length of the semiconductor
Atomic nature of the semiconductor
Shape and atomic nature of the semiconductor
Shape of semiconductor
48.Which of the following statements is true about extrinsic semiconductors?
The gap between the conduction band and the valence bond is more than 16 eV
The gap between the conduction band and the valence bond is about 1 eV
The gap between the conduction band and valence band is 100 eV and more
The conduction band and the valence band overlap.
49.How many valence electrons do trivalent impurities have?
2
3
4
5
50.How many valence electrons does a pentavalent impurity have?
3
4
5
6
51.Which among the following is the most commonly used semiconductor?
Silicon
Carbon
Germanium
Sulphur