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1. When a pentavalent impurity is added to a pure
semiconductor, it becomes _____ semi-conductor.
a. Intrinsic
b. P-type
c. N-type
d. None of these
Ans. c. N-type
2. Pentavalent impurity has _____
a. 3 valence electrons
b. 4 valence electrons
c. 5 valence electrons
d. 6 valence electrons
Ans. c. 5 valence electrons
3. An n-type semiconductor is ____
a. Negatively charged
b. Positively charged
c. Electrically neutral
d. None of these
Ans. c. Electrically neutral
4. In a semiconductor, the energy gap between valence band and
conduction band is about ____.
a. 5eV
b. 1eV
c. 10eV
d. 0eV
Ans. b. 1eV
5. A semiconductor has _______ temperature co-efficient of
resistance.
a. Negative
b. Zero
c. Positive
d. None of these
Ans. a. Negative
5. Resistivity of a semiconductor ____ conductors and insulators
a. is more than that of
b. lies between that of
c. is less than that of
d. None of these
Ans. b. lies between that of
6. Addition of trivalent impurity to a pure semiconductor creates
many _____.
a. Holes
b. Electrons
c. Valent electrons
d. Bound electrons
Ans. a. Holes
7. The charge of a hole is _____.
a. Zero
b. Equal to that of a neutron
c. Equal to that of a proton
d. Equal to that of a electron
Ans. c. Equal to that of a proton
8. In a semiconductor, current conduction is due to ____.
a. Electrons
b. Holes
c. Holes and free electrons
d. None of these
Ans. c. Holes and free electrons
9. A battery connections required for forward bias a pn junctions
are __________.
a. –ve terminal to p and +ve terminal to n
b. +ve terminal to p and -ve terminal to n
c. +ve terminal to p and +ve terminal to n
d. None of these
Ans. b. +ve terminal to p and -ve terminal to n
10. In the depletion region of a pn junction, there is a shortage of
a. Acceptor ions
b. Donor ions
c. Holes and electrons
d. None of the above
Ans. c. Holes and electrons
11. A pn junction acts as a _____.
a. Bidirectional switch
b. Unidirectional switch
c. Controlled switch
d. None of these
Ans. b. Unidirectional switch
12. The leakage current in a pn junction is due to ______ .
a. Majority carriers
b. Minority carriers
c. Junction capacitance
d. None of these
Ans. b. Minority carriers
13. The reverse biased pn junction has a resistance _____.
a. of the order of Ω
b. of the order of KΩ
c. of the order of MΩ
d. None of these
Ans. c. of the order of MΩ
14. With a forward biasing to a pn junction, the width of depletion
layer
a. Decreases
b. Increases
c. Remains the same
d. None of these
Ans. a. Decreases
15. Electrons-hole pairs are produced by
a. Recombination
b. Thermal Energy
c. Ionisation
d. Doping
Ans. b. Thermal Energy
16. An example of N-type of impurity is
a. Boron
b. Gallium
c. Aluminum
d. Arsenic
Ans. d. Arsenic
17. The depletion region is created by
a. Ionisation
b. Diffusion
c. Recombination
d. All of these
Ans. d. All of these
18. The voltage where avalanche occur is called
a. Barrier potential
b. Depletion layer
c. Breakdown voltage
d. Knee voltage
Ans. c. Breakdown voltage
19. The process of adding impurity to an intrinsic semiconductor is
called
a. Atomic modification
b. Doping
c. Recombination
d. Ionisation
Ans. b. Doping
20. The Majority carries in semiconductor are produced by
a. Doping
b. Bound electrons
c. Electron-hole pairs
d. None of these
Ans. a. Doping
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