SEMICONDUCTOR
DIODES & APPLICATIONS
OBJECTIVE
TYPE QUESTIONS BASED ON DIPLOMA LEVEL SYLLABUS FOR THE
DRDO,DMRC,SSC,BHEL,RAILWAYS & OTHER ENGINEERING(DIPLOMA LEVEL) COMPETITIVE EXAMS
1. In a p-type
semiconductor material holes are ________________.
a) majority charge carriers b) minority charge carriers
c) donor atoms d)
acceptor atoms
2. In a p-type semiconductor
material electrons are ________________.
a) majority charge carriers b) minority charge carriers
3. The trivalent impurity atom, like
gallium, added to pure germanium materials termed as
____________.
a) majority charge carriers b)
minority charge carriers
c) donor atoms
d) acceptor atoms
4. In extrinsic semiconductors, conduction
of current is due to ____________.
a) electrons only
b) holes only
c) both electrons and holes d) neither electrons nor holes
5. Doping an intrinsic semiconductor with pentavalent
impurity atom __________________.
a) raises the Fermi level b) lowers the Fermi level
c) do not affect the Fermi level d)
none of the above
6. Doping an
intrinsic semiconductor with trivalent impurity atom __________.
a) raises the Fermi level b) lowers the Fermi level
c) do not affect the Fermi level d)
none of the above
7. In a pure
semiconductor, the Fermi level lies _____________ of the forbidden energy gap.
a) exactly in the middle
b) at the lower part
c) at the upper part
d) none of the above
8. In a p-n
junction, the potential built across the junction, after diffusion has stopped,
is termed
as _______________.
a)
barrier potential
b) developed
potential
c) p-n potential d)
none of the above
9. The barrier
potential is about ______________ of germanium.
a) 0.1V
b) 0.3V
c) 0.7V d)
1.5V
10. The
barrier potential is about ______________ of silicon.
a) 0.1V b)
0.3V
c) 0.7V
d) 1.5V
11. If an external voltage is
applied across the p-n junction such that it
neutralizes the
barrier potential and causes conduction
through the junction, the p-n junction is said to be
______________.
a) forward biased
b) reverse biased
c) un-biased
d) no-biased
12. If an external voltage is applied across the p-n
junction such that the depletion layer widens and the barrier potential
increases, the p-n junction is said to be ______________.
a) forward biased
b)
reverse biased
c)
un-biased d)
no-biased
13. A p-n junction conducts when it is
_________________.
a)
forward biased
b) reverse
biased
c)
un-biased d)
no-biased
14. A p-n junction blocks conduction when it is
________________.
a) forward biased b) reverse biased
c)
un-biased d)
no-biased
15. The direction of conventional current is always
____________ to the direction of drifting
electrons.
a) same
b) opposite
c) can’t say d) none of the
above
16. The slope of DC load line is _______________.
a) –1/IL
b) –1/VL
c) –1/RL
d) –1/If
17. The Iav for
a half-wave rectifier is _____________.
a) Im/π
b) Im/2
c) 2Im/π d)
Im/√2
18. The IRMS for a half-wave
rectifier is ______________.
a) Im/π b) Im/2
c) 2Im/ π d)
Im/√2
19. The Iav for
a full-wave rectifier is _____________.
a) Im/π b)
Im/2
c) 2Im/
π d)
Im/√2
20. The IRMS for
a full-wave rectifier is _____________.
a) Im/π b)
Im/2
c) 2Im/ π d) Im/√2
21. The efficiency of a half-wave rectifier is
_____________.
a) 40.6%
b) 81.2%
c)
0.483% d)
1.21%
22. The efficiency of a full-wave rectifier is
_____________.
a) 40.6%
b) 81.2%
c)
0.483% d)
1.21%
23. The ripple factor of a half-wave rectifier is
_____________.
a) 40.6 b)
81.2
c) 0.483 d) 1.21
24. The ripple factor of a full-wave rectifier is
_____________.
a) 40.6 b)
81.2
c) 0.483
d) 1.212
25. An inductor
___________ to pass through it.
a) allows DC
b) blocks DC
c)
allows AC d)
blocks AC
26. A capacitor ___________ to pass through
it.
a)
allows DC b)
blocks DC
c) allows AC d) blocks AC
27. The switch
off time of diodes is longer due to _______________.
a) the diffusion capacitance b) the forward
bias
c) the reverse bias d) none of the
above
28. The total number of electrons in an atom depends
upon ____________.
a)
The atomic mass
b) the atomic weight
c) The atomic number d) the atomic size
29.
In any atom, the number of electrons in the last orbit (i.e., the outermost orbit or the valence orbit) is limited
to ________________.
a) 4 b) 8
c) 10 d)
12
30. In any atom, the outermost orbit is called
______________.
a) Valence orbit
b) energy band
c)
Conduction band d)
forbidden band
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