1.The resistivity of semiconductor................. conductors and insulators.

(a) is more than that

of (b) lies between that of (c) is less than that of (d) none of the above
2. A semiconductor is formed by.....................bonds. (a) covalent (b) electrovalent (c) co-
ordinate (d) none of the above
3. The most commonly used semiconductor is............................ (a) germanium (b) carbon (c)
sulphur (d) silicon
4. In a semiconductor, the energy gap between valence band and conduction band is
about........ (a) 5 eV (b) 10 eV (c) 15 eV (d) 1 eV
5. A semiconductor has ...............temperature co-efficient of resistance. (a) negative (b)
positive (c) zero (d) none of the above
6. A semiconductor generally has ................valence electrons. (a) 2 (b) 3 (c) 4 (d) 6
7. A crystal diode has............................ (a) two pn junctions (b) one pn junction (c) three pn
junctions (d) none of the above
8. A crystal diode has forward resistance of the order of............................ (a)  (b) k (c)
M (d) none of the above
9. When a pure semiconductor is heated, its resistance.................... . (a) goes down (b) goes
up (c) remains the same (d) none of the above
10. The reverse current in a diode is of the order of......................... (a) A (b) mA (c) A (d)
kA
11. When a pentavalent impurity is added to a pure semiconductor, it becomes...................
semi-conductor. (a) intrinsic (b) n-type (c) p-type (d) none of the above
12. Addition of pentavalent impurity to a semiconductor creates many.......................... . (a)
free electrons (b) holes (c) valence electrons (d) bound electrons
13. A pentavalent impurity has....................... (a) 3 valence electrons (b) 6 valence electrons
(c) 4 valence electrons (d) 5 valence electrons
14. An n-type semiconductor is.......................... (a) positively charged (b) electrically neutral
(c) negatively charged (d) none of the above
15. A trivalent impurity has.......................... . (a) 3 valence electrons (b) 5 valence electrons
(c) 6 valence electrons (d) 4 valence electrons
16. Addition of trivalent impurity to a pure semiconductor creates many.................. (a) free
electrons (b) valence electrons (c) holes (d) bound electrons
17. The forward voltage drop across a silicon diode is about............................ (a) 2.5 V (b) 3
V (c) 0.7 V (d) 10 V
18. A pentavalent impurity is called....................... . (a) donor impurity (b) acceptor impurity
(c) ionic impurity (d) none of the above
19.The charge of a hole is ................... . (a) zero (b) equal to that of a proton (c) equal to that
of an electron (d) equal to that of a neutron
20. As a general rule, holes are found only in...................... (a) metals (b) semiconductors (c)
insulators (d) resistance materials
21. A semiconductor has a.................... (a) negative temperature co-eff. of resistance (b)
positive temperature co-eff. of resistance (c) constant temperature co-eff. of resistance (d)
none of these
22. To obtain n-type semiconductor, the impurity added to pure semiconductor is.......... (a)
trivalent (b) tetravalent (c) pentavalent (d) none of these
23. To obtain p-type semiconductor, the impurity added to pure semiconductor is.......... (a)
trivalent (b) tetravalent (c) pentavalent (d) none of these
24. An n-type semiconductor has electrons as majority carriers, due to this, material attains
negative charge on it. (a) true (b) false
25. A p-type and n-type semiconductor attains positive and negative charge respectively. (a)
true (b) false
26. In a p-type semiconductor, the majority carriers are................ (a) holes (b) electrons (c)
positive ions (d) negative ions
27. When a p-n junction is prepared, a layer is formed around the junction called depletion
layer because..................... (a) p-type semiconductor has holes as majority carriers (b) n-type
semiconductor has electrons as majority carriers (c) the charge carriers are depleted in this
region (d) all of these
28. For a germanium p-n junction, the maximum value of barrier potential is (a) 0.3 V (b) 0.7
V (c) 1.3 V (d) 1.3 V
29. When a p-n junction is forward-biased, (a) it offers a low resistance, and a large current
flows through it (b) if offers a high resistance, and a small current flows through it (c) it acts
as an insulator and no current flows through it. (d) the width of depletion layer increases.
30. When a p-n junction is reverse-biased. (a) the width of depletion layer increases (b) it
offers a high resistance (c) a small current flows through it because of minority carriers (d) all
of these
31. If the arrow of a crystal diode symbol is positive w.r.t. bar, then diode is ............ biased.
(a) reverse (b) forward (c) none of the two (d) forward or reverse
32. A crystal diode is used as........................ (a) an amplifier (b) a rectifier (c) an oscillator (d)
a voltage regulator
33. The dc resistance of a crystal diode is ................... that of its ac resistance. (a) the same as
(b) more than (c) less than (d) none of the above
34. An ideal crystal diode is one which behaves as a perfect .................when forward-biased.
(a) conductor (b) insulator (c) resistance material (d) none of the above
35. The reverse resistance and forward resistance of crystal diode have a ratio of
about................ (a) 1:1 (b) 1000:1 (c) 100:1 (d) 2:1
36. The leakage current in a crystal diode is due to.......................... (a) minority carriers (b)
majority carriers (c) junction capacitance (d) none of the above
37. If temperature of a crystal diode increases, leakage current........................ (a) remains the
same (b) decreases (c) increases (d) becomes zero
38. The PIV rating of a crystal diode is...................its breakdown voltage. (a) lower than (b)
more than (c) the same as (d) none of the above
39. If the doping level of a crystal diode is increased, the breakdown voltage.............. (a)
remains the same (b) is decreased (c) is increased (d) none of the above
40. If doping level in a crystal diode is increased, the width of depletion layer.......................
(a) remains the same (b) is increased (c) is decreased (d) none of above
41. A zener diode has..................... (a) one p-n junction (b) two p-n junctions (c) three p-n
junctions (d) none of the above
42.A zener diode is used as........................... (a) an amplifier (b) a rectifier (c) a voltage
regulator (d) a multivibrator
43. The doping level in a zener diode is ........................ that of a crystal diode. (a) more than
(b) less than (c) the same as (d) none of the above
44. Potential barrier at a p-n junction is established due to the charges on either side of the
junction. These charges are........ (a) majority carriers (b) minority carriers (c) both a and b (d)
donor and acceptor ions
45. In a p-n junction, holes diffuse from the p-region to n-region because (a) they move
across the junction by the potential difference (b) free electrons available in the n-region
attract them (c) the holes concentration in the p-region is greater as compared to n-region (d)
all of these
46. In a crystal diode, the barrier potential offers opposition to only (a) free electrons in n-
region (b) holes in p-region (c) majority carriers in both regions (d) minority carriers in both
regions.
47. When a reverse-bias is applied to a crystal diode, it (a) raises the potential barrier (b)
lowers the potential barrier (c) increases the majority-carrier current greatly (d) none of these
48. When a p-n junction is forward-biased (a) electrons in the n-region are injected into the p-
region. (b) holes in the p-region are injected into the n-region. (c) both a and b (d) none of
these
49. When a forward-bias is applied to a crystal diode, it (a) raises the potential barrier (b)
lowers the potential barrier (c) reduces the majority-carrier current to zero (d) none of these
50. Avalanche breakdown in a crystal diode occurs when (a) the potential barrier is reduced
to zero (b) forward current exceeds a certain value (c) reverse-bias exceeds a certain value
(d)all of these
51. The voltage across the resistor is

(a) 0.4V (b) 0V (c) 0.2V (d) 0.42V

52. When a diode is used as a rectifier, the most important consideration is (b) doping level (b)
PIV (d) forward resistance (d) none of the above
53. In a full-wave rectifier without filter, the ripple factor is (a) 0.482 (b) 1.21 (c) 1.79 (d)
2.05
54. The value of ripple factor of a half-wave rectifier without filter is approximately (a) 1.21
(b) 0.21 (c) 2.22 (d) 2.01
55. The transformer utilization factor of a half-wave rectifier is approximately (a) 0.60 (b)
0.29 (c) 0.89 (d) 1.11
56. If the output voltage of a bridge rectifier is 100V, the PIV of diode will be (a) 100√2 � (b)
100/� � (c) 100� � (d) 100�/2 �
57. In the voltage regulator shown below, if the current through the load decreases, (a) the
current through R1 will increase. (b) the current through R1 will decrease. (c) Zener diode
current will increase. (d) Zener diode current will decrease
58. Rectification efficiency of a full-wave rectifier without filter is nearly equal to (a) 40.6%
(b) 61.3% (c) 100% (d) 81.2%
59. Rectification efficiency of a half-wave rectifier without filter is nearly equal to (a) 100%
(b) 80.8% (c) 50.5% (d) 40.6%
60. In a clamping circuit, the peak-to peak voltage of the waveform being clamped is (a)
affected by the clamping (b) not affected by the clamping (c) determined by the clamping
voltage value (d) determined by the ratio of rms voltage of the waveform and the clamping
voltage
61. In a half-wave rectifier, the load current flows (a) only for the positive half-cycle of the
input signal (b) for less than half-cycle of the input signal (c) for more than half-cycle of the
input signal (d) for whole cycle of the input signal
62. In a full-wave rectifier, the current in each diode flows for (a) whole cycle of the input
signal (b) half-cycle of the input signal (c) more than half-cycle of the input signal (d) none
of these
63. In full-wave rectification, if the input frequency is 50 Hz, then the output frequency will
be (a) 50 Hz (b) 75 Hz (c) 100 Hz (d) 200 Hz
 64. In a centre-tapped full-wave rectifier, if Vm is the peak voltage between the centre-tap
and one end of the secondary, the maximum voltage coming across the reverse-biased diode
is (a) Vm (b) 2 Vm (c) Vm /2 (d) Vm /2
65. In a bridge-type full-wave rectifier, if Vm is the peak voltage across the secondary of the
transformer, the maximum voltage coming across each reverse-biased diode is (a) Vm (b) 2
Vm (c) Vm /2 (d) Vm /2
66. If the peak value of the input voltage to a half-wave rectifier is 28.28 volts and no filter is
used, the maximum dc voltage across the load will be (a) 20.2V (b) 15 V (c) 9 V (d) 14.14 V
67. The turns ratio of a transformer used in a half-wave rectifier is 10:1.The primary is
connected to the power mains, 220 V, 50 Hz. If the diode resistance in forward-bias is
zero ,the dc voltage across the load will be nearly (a) 15 V (b) 10 V (c) 12 V (d) 8 V
68. The turns ratio of a transformer used in a full-wave rectifier is 10:1.The primary is
connected to the power mains, 220 V, 50 Hz. If the diode resistance in forward-bias is
zero ,the dc voltage across the load will be nearly (a) 60 V (b) 40 V (c) 20 V (d) 50 V
69. Zener diodes are used in regulator networks to (a) generate voltage (b) consume power (c)
maintain a fixed voltage across the load resistor (d) none of these
70. A silicon diode in a half-wave rectifier has a barrier potential of 0.7V. This has the effect
of (a) reducing the peak output voltage by 0.7V (b) increasing the peak output voltage by
0.7V (c) reducing the peak input voltage by 0.7V (d) no effect
71. The light-emitting diode (LED) (a) is usually made from metal oxide. (b) is used in reverse-biased
junction. (c) gives a light output which increases with temperature. (d) emits light due to
recombination of holes and electrons.

72. The material used for the construction of LED is (a) Si (b) Ge (c) GaAsP (d) None of these

73. As the temperature across LED increases (a) the intensity of light emitted decreases. (b) the
intensity of light emitted increases. (c) there is no change in the intensity of light emitted. (d) it
simply switches-off.

74. In a forward-biased photodiode, with increase in incident light intensity the diode current (a)
increases. (b) remains constant. (c) decreases. (d) remains constant, the voltage drop across the
diode increases

75. With reference to the reverse-biased p-n junction photodiode, the following statements are
made. (1) The number of electron hole pairs due to illumination is proportional to the number of
incident photons. (2) While the photon current is essentially due to minority carriers, the saturation
current is due to majority carrier flow. (3) The photon current and the saturation current are in the
same direction. (4) The effect of illumination can be considered as a majority carrier injection. Of the
four statements, the true statements are (a) All four (b) (1) and (2) (c) (2) and (3) (d) (1) and (3)

76. In LED, light is emitted because (a) recombination of charge takes place. (b) we make the light
fall on LED. (c) diode emits light when heated. (d) none of these.

77. LEDs do not require (a) heating. (b) warm up time. (c) Both (a) and (b) above. (d) None of the
above.
78. Which of the following material is used for infrared LEDs? (a) Gallium arsenide (b) Calcium
phosphide(c) Silicon (d) None of the above

79.The power consumption of LEDs may be of the order of

(a) 5 to 10 nanowatt. (b) 5 to 10 microwatt.

(c) 5 to 10 milliwatt. (d) 5 to 10 watt.

80. With reference to the reverse-biased p-n junction photodiode, the following statements

are made.

(1) The number of electron hole pairs due to illumination is proportional to the number

of incident photons.

(2) While the photon current is essentially due to minority carriers, the saturation

current is due to majority carrier flow.

(3) The photon current and the saturation current are in the same direction.

(4) The effect of illumination can be considered as a majority carrier injection.

Of the four statements, the true statements are

(a) All four (b) (1) and (2)

(c) (2) and (3) (d) (1) and (3)

81. A pure semiconductor is often referred to as A) extrinsic semiconductor B) intrinsic

semiconductor C) doped semiconductor D) none of the above

82. In a p-type semiconductor, the majority current Carriers areA) free electrons B) valence electrons
C) holes D) protons

83. A diode is aA) nonlinear device B) linear device C)unidirectional device D)both a and c

84. What is the DC output voltage of an unfiltered half wave rectifier whose peakoutput voltage is
9.8 voltA) 6.23 volt B) 19.6 volt C) 9.8 volt D) 3.1 volt(Hint : Vdc =0.318 * Vo/p(pk))

85. In n-type semiconductor the minority current carriers are A) free electrons B) protons C) valence
electrons D) the holes

86. To a first approximation a forward biased diode is treated like aA) open switch with infinite
resistance B) closed switch with the voltage drop of zero volt C) close switch in series with the
battery voltage of 0.7 volt D) lose switch in series with a small resistance and a battery

87. What is the frequency of the capacitor ripple voltage in a full wave rectifier circuit if the
frequency of the transformer secondary voltage is 60 Hertz A) 60 Hertz B)120 Hertz (Hint : F(out)=2
F(in)) C) 50 Hertz D) be this is impossible to determine

88. In a full wave rectifier the DC load current equals 1 ampere, how much DC current is carried by
each diode A) 1/2 A (Hint: I(diode)=I(load)/2) B)1ampere B) 1 ampere C)2 ampere D)0 Ampere
89. To forward biased diode A) the cathode voltage must be positive with respect to the anode B)
the anode voltage must be positive with respect to its cathode C) the anode voltage must be
negative with respect to its cathode D) none of the above

90. The sharing of valence electron in a silicon crystal is called A) doping B) coupling C) covalent
bonding D) the avalanche effects

91. Reverse bias diode acts like A) open switch B) close switch C) small resistance D) none of the
above

92. When used as a voltage regulator, zener diode is normally A) not baised B) forward biased C)
reverse biased D) none of the above

93. For a germanium diode, the barrier potential isA) 0.3 volt B) 0.3 eV C) 0.7 volt D) 0.7 eV

94. The approximate voltage drop across a forward biased LED isA) 0.3 volt B)2.0 volt C) 5.6 voltD)
0.7 volt

95. The output from an unfiltered half wave or full wave rectifier is a A) smooth DC voltage B) steady
DC voltage C) pulsating DC voltage D) AC voltage

96. In the breakdown region ,a zener diode behaves like a .... source A) constant voltageB) constant
current C) constant resistance D) none of the above

97. If the temperature of Crystal diode increases ,the leakage current… A) remains the same B)
decreases C) increases D) become zero

98. When the crystal current diode is large, the bias is A) forward B) inverse C) poor D) reverse

99. for the same secondary voltage , output voltage from a centre tap rectifiers..... than that of
bridge rectifier.A) twice B) thrice C) one half D) four times

100. Zener diode is used as A) an amplifier B) a voltage regulator C) a multivibrator D) a rectifier

101. The disadvantage of a half wave rectifier is that the A) components are expensive B) diodes
must have a higher power rating C) output is difficult to filter D) none of the above

102. A zener diode has ... breakdown voltage A) undefined B) zero C) sharp D) none of the above

103. Zener diode is always... connected A) reverse B) either reverse or forward C) forwardD) none of
the above

104. If the PIV rating of a diode is exceeded,.....A) the diode conducts poorly B) the diode is
destroyed C) the diode behaves like a zener diode D) none of the above

105. Zener diode is destroyed if it… A) is forward biaed B) is reverse biased C)carries more than the
rated current D) none of the above

106. If the doping level of a crystal diode is increased ,the breakdown voltage A) remains the same B)
is increased C) is decreased D) none of the above

107. The ripple factor of a half wave rectifier is… A) 2 B) 1.21 C) 2.5 D) 0.48

108. The maximum efficiency of a half wave rectifier is.......A) 40.6% B) 81.2%C) 50% D) 25%

109. The most widely used rectifier is A) half wave rectifier B) centre-tap full wave rectifier C) bridge
full-wave rectifier D) none of the above
110. Zener diode has… A)1 PN junction B) 2 PN junction C) 3 PN junction D) 4 PN junction

111. Avalanche breakdown in a crystal diode occurs when A) the potential barrier is reduced to zero
B) forward current exceeds a certain value C) reverse bias exceeds a certain value D) none of the
above

112. When crystal diode is used as a rectifier, the most important consideration is.… A) forward
characteristic B) doping level C) reverse characteristic D) PIV rating

113. When the graph between current through and voltage across a device is a straight line, the
device is referred to a A) linear B) active C) nonlinear D) passive

114. The leakage current in a crystal diode is due to A) minority charge carriers B) majority charge
carriers C) junction capacitance D) none of the above

115. The PIV rating of a crystal diode is.... .....that of equivalent vacuum diodeA) same as B) lower
than C) more than D) none of the above

116. The knee voltage of a crystal diode is approximately equal to.. A) barrier potential B)
breakdown voltage C) applied voltage D) forward voltage

117. If the doping level in a crystal diode is increased , the width of depletion layer A) remains the
same B) is increased C) is decreased D) none of the above

118. The doping level in a zener diode is ................................. that of a crystal diode A) same as B)
more than C) less than D) none of the above

119. A series resistance is connected in the zener circuit to… A) protect the zener diode B) properly
reverse bias the zener C) properly forward bias the zener D) none of the above

120. zener diode is a .... device A) non-linear B) linear C) amplifying D) none of the above

121. In a half wave rectifier, the load current flows for A) the complete cycle of input signal B) only
for positive half cycle of the input signal C) less than half cycle of the input signal D) more than half
cycle but less than the complete cycle of input signal
1. Transistor is a:
(a) Current controlled current device (b) Current controlled voltage device (c) Voltage
controlled current device (d) Voltage controlled voltage device
2. A transistor has.........................… (a) one p-n junction (b) two p-n junctions (c) three p-n
junctions (d) four p-n junctions
3. The number of depletion layers in a transistor is.............................… (a) three (b) two (c)
one (d) four
4. In an npn transistor, p region is called.......................… (a) collector (b) emitter(c) base (d)
none of the above
5. The element that has the biggest size in a transistor is........................… (a) base (b) emitter
(c) collector (d) collector-base junction
6. The collector of a transistor is...............................doped. (a) heavily (b) lightly (c)
moderately (d) none of the above
7. The arrowhead on the transistor symbol points in the director of (a) electrons flow in the
emitter region (b) minority carriers flow in the emitter region (c) majority carriers flow in the
emitter region (d) conventional current flow in the emitter region
8. The base of a transistor is........................... doped. (a) lightly (b) moderately (c) heavily (d)
none of the above
9. The base current of a transistor is typically: (a) less than emitter current (b) greater than
emitter current (c) same as emitter current (d) equal to the sum of emitter and collector
currents
10. The emitter of a transistor is .............................. doped. (a) lightly (b) heavily (c)
moderately (d) none of the above
11. The transistor must be operated in _____ when employed as an amplifying device: (a)
saturation region (b) cut-off region (c) active region (d) any of the three
12. When both the junctions of a transistor are forward-biased, it is said to be in the:(a) active
region (b) passive region(c) cut-off region (d) saturation region
13. In a correctly biased npn transistor: (a) The base is positive with respect to collector(b)
The base is positive with respect to emitter(c) The base is positive with respect to both
emitter and collector(d) None of these
14. Biasing represents ........................ conditions.(a) ac (b) dc(c) both dc and ac (d) none of
the above
15. For faithful amplification, the value of VBE should ............. for silicon transistor.(a) be
zero (b) be 0.01 V(c) not fall below 0.7V (d) be between 0V and 0.1 V
16. A transistor is said to be in a quiescent state when(a) it is unbiased (b) no signal is applied
to the output (c) no signal is applied to the input (d) emitter junction is just biased equal to
collector junction
17. The ICBO is the current that flows when some dc voltage is applied (a) in the forward
direction to the emitter junction with collector open (b) in the reverse direction to the emitter
junction with collector open (c) in the reverse direction to the collector junction with emitter
open (d) in the forward direction to the collector junction with emitter open
18. ICBO in a transistor can be reduced by: (a) reducing IB (b) reducing VCC (c) reducing IE
(d) reducing the temperature
19. A junction transistor with β = 49 and ICO = ICBO = 1μA has IB = 10μA. The value of
ICis given in μA by: (a) 441 (b) 490 (c) 539 (d) 540
20. In a transistor, if IC = 9.95mA and IE = 10mA then the value of β is given by: (a) 199 (b)
99 (c) 9 (d) 1
21. The input resistance of a common-emitter transistor is of the order: (a) 1 MΩ (b) 1 KΩ(c)
0.01Ω (d) 0.001Ω
22. Lowest output resistance is obtained in: (a) CB (b) CE(c) CC (d) None of these
23. The current gain of a transistor is: (a) the ratio of collector current to emitter current (b)
the ratio of collector current to base current (c) the ratio of base current to collector current(d)
the ratio of emitter current to collector current
24. The leakage current in CE configuration may be around: (a) few nanoamperes (b) few
microamperes (c) few hundred microamperes (d) few milliamperes
25. If a transistor emitter current is 2 mA, the collector current is: (a) greater than 2 mA (b)
less than 2 mA (c) equal to 2 mA (d) equal to 4 mA
26. In a pnp transistor in the active region of operation, the base current is due to: (a) holes
injected into the emitter from base (b) holes entering the base from the terminal for
recombination (c) only saturation current due to reverse bias of collector junction(d) electrons
recombining with a part of the diffusing holes in the base region.
27. For transistor action (a) the base region must be very thin and lightly doped (b) the
emitter junction should be forward biased and collector junction should be reverse biased(c)
the emitter should be heavily doped so that it can supply the required amount of majority
carriers (d) all of these
28. In CB configuration, the output V-I characteristics of a transistor are drawn by taking (a)
VCB versus IC for constant IE (b) VCB versus IB for constant IE(c) VCE versus IC for
constant IE (d) VCE versus IB for constant IE
29. In CE configuration, the input V-I characteristics are drawn by taking (a) VCE versus IC
for constant value of IE (b) VBE versus IE for constant value of VCE (c) VBE versus IB for
constant value of IC (d) VBE versus IB for constant value of VCE
30. The beta of a transistor may be determined directly from the curve plotted between(a)
VCE and IC for constant IB (b) VCE and IC for constant IE (c) VCE and IE for constant IB
(d) VBE and IE for constant VCE

31. In CE mode of transistor, the most noticeable effect of a small increase in temperature is
(a) the increase in output resistance (b) the increase in leakage current ICEO (c) the decrease
in ac current gain (d) the increase in ac current gain
32. The current ICEO is (a) The emitter current in the CC connected transistor with zero base
current (b) The collector current in the CE connected transistor with zero emitter current (c)
The collector current in the CE connected transistor with zero base current (d) Same as ICBO

33. In CE configuration, the output V-I characteristics are drawn by taking (a) VCE versus IC
for constant value of IE (b) VCE versus IC for constant value of IB (c) VCE versus IE for
constant value of VCB (d) none of these
34. The emitter current in a junction with normal bias (a) is almost equal to the base current(b)
is equal to the sum of IB and IC (c) changes greatly by a small change in collector bias
voltage (d) is equal to ICBO
35. In cut-off region: (a) both emitter and collector junctions are forward-biased(b) both
emitter and collector junctions are reverse-biased(c) emitter junction is forward-biased ,
collector junction is reverse-biased (d) no biasing is required
36. Emitter bias depends on: (a) Signal input (b) IE (c) Gain (d) IC
37. Which of the following configurations is normally used in cascading? (a) common-
emitter (b) common-base (c) common-collector (d) All of these
38. In a pnp transistor biased to operate in the active region, the current in the base region
consists of: (a) only holes (b) only electrons (c) predominantly holes (d) predominantly
electrons
39. In a BJT, ICO = ICBO = 2μA given α = 0.99, the value of ICEO is: (a) 2μA (b) 99μA (c)
198μA (d) 200μA
40. ICBO of a transistor can be decreased by decreasing: (a) IB (b) IC (c) IE (d) none of these
41. Emitter current in a CE circuit: (a) can be made zero as in a CB circuit (b) can be made
zero by reverse-biasing BE junction (c) can be made zero by forward-biasing BE junction (d)
can be made zero by reverse-bias of 0.1 V for silicon and 0V for germanium transistor
42. A transistor, when connected in CE mode, has(a) low input resistance and low output
resistance (b) high input resistance and high output resistance(c) high input resistance and
low output resistance (d) medium input resistance and high output resistance
43. The CE amplifier circuits are preferred over CB amplifier circuits because they have(a)
lower amplification factor (b) larger amplification factor (c) high input resistance and low
output resistance (d) none of these
44. The silicon transistors are more widely used than germanium transistors because(a) they
have smaller leakage current (b) they have better ability to dissipate heat (c) they have
smaller depletion layers (d) they have larger current carrying capacity
45. The common collector transistor configuration has: (a) high current gain and high input
resistance (b) high current gain and low input resistance (c) low current gain and high input
resistance (d) low current gain and low input resistance
46. A transistor has ..................… 1. one pn junction 2. two pn junctions 3. three pn junctions
4. four pn junctions
47. The number of depletion layers in a transistor is .........… 1. four 2. three 3. one 4. two
48. The base of a transistor is .............. doped 1. heavily 2. moderately 3. lightly 4. none of
the above
49. The element that has the biggest size in a transistor is ....................1. collector 2. base 3.
emitter 4. collector-base-junction
Q5. In a pnp transistor, the current carriers are ..........… 1. acceptor ions 2. donor ions 3. free
electrons 4. holes
Q6. The collector of a transistor is ............. doped 1. heavily 2. moderately 3. lightly 4. none
of the above
Q7. A transistor is a ............... operated device 1. current 2. voltage 3. both voltage and
current 4. none of the above
Q8. In a npn transistor, ................ are the minority carriers 1. free electrons 2. holes 3. donor
ions 4. acceptor ions
Q9. The emitter of a transistor is ..................... doped 1. lightly 2. heavily 3. moderately4.
none of the above
Q10. In a transistor, the base current is about .............. of emitter current 1. 25% 2. 20%
3.35 % 4. 5%
Q11. At the base-emitter junctions of a transistor, one finds ............… 1. a reverse bias 2. a
wide depletion layer 3. low resistance 4. none of the above
Q12. The input impedance of a transistor is ..........… 1. high 2. low 3. very high4 . almost
zero
Q13. Most of the majority carriers from the emitter .................… 1. recombine in the base 2.
recombine in the emitter 3. pass through the base region to the collector 4. none of the above
Q14. The current IB is .........… 1. electron current 2. hole current 3. donor ion current 4.
acceptor ion current
Q15. In a transistor .................… IC = IE + IB , IB = IC + IE , IE = IC – IB, IE = IC + IB
Q16. The value of α of a transistor is ..........▪ more than 1 ▪ less than 1 ▪ 1▪ none of the above
Q17. IC = αIE + .............1. IB 2. ICEO 3. ICBO 4. βIB
Q18. The output impedance of a transistor is ..............… 1. high 2. zero 3. low 4. very low
Answer : 1
Q19. In a tansistor, IC = 100 mA and IE = 100.2 mA. The value of β is .........… 1. 100 2. 50
3. about 1 4. 200
Answer : 4
Q20. In a transistor if β = 100 and collector current is 10 mA, then IE is .........… 1. 100 mA 2.
100.1 mA 3. 110 mA 4. none of the above
Q21. The relation between β and α is ..............1. β = 1 / (1 – α ) 2. β = (1 – α ) / α 3. β = α /
(1 – α ) 4. β = α / (1 + α )
Q22. The value of β for a transistor is generally ....................1. 1 2. less than 1 3. between 20
and 500 4. above 500
Q23. The most commonly used transistor arrangement is ............... arrangement 1. common
emitter 2. common base 3. common collector 4. none of the above
Q24. The input impedance of a transistor connected in ................. arrangement is the highest1.
common emitter 2. common collector 3. common base 4. none of the above
Q25. The output impedance of a transistor connected in ................ arrangement is the highest
1. common emitter 2. common collector 3. common base 4. none of the above
Q26. The phase difference between the input and output voltages in a common base
arrangement is .............… 1. 180o 2. 90o 3. 270o 4. 0o
Q27. The power gain in a transistor connected in ................ arrangement is the highest 1.
common emitter 2. common base 3. common collector 4. none of the above
Q28. The phase difference between the input and output voltages of a transistor connected in
common emitter arrangement is ...............… 1. 0o 2. 180o 3. 90o 4. 270o
Q29. The voltage gain in a transistor connected in ................... arrangement is the highest 1.
common base 2. common collector 3. common emitter4. n one of the above
Q30. As the temperature of a transistor goes up, the base-emitter resistance ............… 1.
decreases 2. increases 3. remains the same 4. none of the above
Q31. The voltage gain of a transistor connected in common collector arrangement is...........1.
equal to 1 2. more than 10 3. more than 100 4. less than 1
Q32. The phase difference between the input and output voltages of a transistor connected in
common collector arrangement is ..................1. 180o 2. 0o 3. 90o 4. 270o
Q33. IC = β IB + ...........1. ICBO 2. IC 3. ICEO 4. αIE
Q34. IC = [α / (1 – α )] IB + .............1. ICEO 2. ICBO 3. IC 4. (1 – α ) IB
Q35. IC = [α / (1 – α )] IB + [........ / (1 – α )] 1. ICBO 2. ICEO 3. IC 4. IE
Q36. BC 147 transistor indicates that it is made of ...........… 1. germanium 2. silicon 3.
carbon 4. none of the above
Q37. ICEO = (.........) ICBO 1. β 2. 1 + α 3. 1 + β 4. none of the above

Q38. A transistor is connected in CB mode. If it is not connected in CE mode with same bias
voltages, the values of IE, IB and IC will ...........… 1. remain the same 2. increase3. decrease
4. none of the above
Q39. If the value of α is 0.9, then value of β is ........… 1. 9 2. 0.9 3. 900 4. 90
Q40. In a transistor, signal is transferred from a ............... circuit 1. high resistance to low
resistance 2. low resistance to high resistance 3. high resistance to high resistance 4. low
resistance to low resistance
Q41. The arrow in the symbol of a transistor indicates the direction of ..........… 1. electron
current in the emitter 2. electron current in the collector 3. hole current in the emitter 4. donor
ion current
Q42. The leakage current in CE arrangement is ................ that in CB arrangement 1. more
than 2. less than3. the same as 4. none of the above
Q43. A heat sink is generally used with a transistor to .........… 1. increase the forward
current2. decrease the forward current 3. compensate for excessive doping 4. prevent
excessive temperature rise
Q44. The most commonly used semiconductor in the manufacture of a transistor is .............1.
germanium 2. silicon 3. carbon 4. none of the above
Q45. The collector-base junction in a transistor has ..............… 1. forward bias at all times 2.
reverse bias at all times 3. low resistance 4. none of the above
Q46. When transistors are used in digital circuits they usually operate in the ..........… 1.
active region 2. breakdown region 3. saturation and cutoff regions 4. linear region
Q47. Three different Q points are shown on a dc load line. The upper Q point represents
the ..........… 1. minimum current gain 2. intermediate current gain 3. maximum current gain 4.
cutoff point
Q48. A transistor has a of 250 and a base current, IB, of 20 A. The collector current, IC,
equals to .............… 1. 500 μA 2. 5 mA 3. 50 mA 4. 5 A
Q49. A current ratio of IC/IE is usually less than one and is called ............ 1. beta 2. theta 3.
alpha 4. omega
Q50. With the positive probe on an NPN base, an ohmmeter reading between the other
transistor terminals should be ...… 1. open 2. infinite 3. low resistance 4. high resistance
Q51. In a CE configuration, an emitter resistor is used for ...… 1. stabilization 2. ac signal
bypass 3. collector bias 4. higher gain
Q52. Voltage-divider bias provides .......… 1. an unstable Q point 2. a stable Q point 3. a Q
point that easily varies with changes in the transistor’s current gain 4. a Q point that is stable
and easily varies with changes in the transistor’s current gain
Q53. To operate properly, a transistor’s base-emitter junction must be forward biased with
reverse bias applied to which junction? 1. collector-emitter 2. base-collector 3. base-emitter 4.
collector-base
Q54. The ends of a load line drawn on a family of curves determine ...… 1. saturation and
cutoff 2. the operating point 3. the power curve 4. the amplification factor
Q55. If VCC = +18 V, voltage-divider resistor R1 is 4.7 k , and R2 is 1500 , then the base
bias voltage is .......… 1. 8.7 V 2. 4.35 V 3. 2.9 V 4. 0.7 V
Q56. The C-B configuration is used to provide which type of gain? 1. voltage 2. current 3.
resistance 4. power
Q57. The Q point on a load line may be used to determine .........… 1. VC 2. VCC 3. VB 4.
IC
Q58. A transistor may be used as a switching device or as a ..........… 1. fixed resistor 2.
tuning device 3. rectifier 4. variable resistor
Q59. If an input signal ranges from 20–40 A (microamps), with an output signal ranging
from .5–1.5 mA (milliamps), what is the ac beta? 1. 0.05 2. 20 3. 50 4. 500
Q60. Beta’s current ratio is ........1. IC/IB 2. IC/IE 3. IB/IE 4. IE/IB
Q61. A collector characteristic curve is a graph showing ...........1. emitter current (IE) versus
collector-emitter voltage (VCE) with (VBB) base bias voltage held constant 2. collector
current (IC) versus collector-emitter voltage (VCE) with (VBB) base biasvoltage held
constant 3. collector current (IC) versus collector-emitter voltage (VC) with (VBB) base
biasvoltage held constant 4. collector current (IC) versus collector-emitter voltage (VCC)
with (VBB) base bias voltage held constant
Q62. With low-power transistor packages, the base terminal is usually the .......… 1. tab end 2.
middle 3. right end 4. stud mount
Q63. When a silicon diode is forward biased, VBE for a CE configuration is .....… 1. voltage-
divider bias 2. 0.4 V 3. 0.7 V 4. emitter voltage
Q64. What is the current gain for a common-base configuration where IE = 4.2 mA and IC =
4.0 mA? 1. 16.8 2. 1.05 3. 0.2 4. 0.95
Q65. With a PNP circuit, the most positive voltage is probably .........… 1. ground 2. VC 3.
VBE 4. VCC
Q66. If a 2 mV signal produces a 2 V output, what is the voltage gain? 1. 0.001 2. 0.004
3. 100 4. 1000
Q67. Most of the electrons in the base of an NPN transistor flow .........… 1. out of the base
lead 2. into the collector 3. into the emitter 4. into the base supply
Q68. In a transistor, collector current is controlled by ........… 1. collector voltage 2. base
current 3. collector resistance 4. all of the above
Q69. Total emitter current is .........… 1. IE – IC 2. IC + IE3. IB + IC4. IB – IC
Q70. Often a common-collector will be the last stage before the load; the main function(s) of
this stage is to ..........… 1. provide voltage gain 2. provide phase inversion 3. provide a high-
frequency path to improve the frequency response 4. buffer the voltage amplifiers from the
low-resistance load and provide impedancematching for maximum power transfer
Q71. For a CC configuration to operate properly, the collector-base junction should be
reverse biased, while forward bias should be applied to ............... junction. 1. collector-
emitter 2. base-emitter 3. collector-base 4. cathode-anode
Q72. The input/output relationship of the common-collector and common-base amplifiers
is ........… 1. 270 degrees 2. 180 degrees 3. 90 degrees 4. 0 degrees
Q73. If a transistor operates at the middle of the dc load line, a decrease in the currentgain
will move the Q point ..........… 1. off the load line 2. nowhere 3. up 4. down
Q74. Which is the higher gain provided by a CE configuration? 1. voltage 2. current
3. resistance 4. power
Q75. What is the collector current for a CE configuration with a beta of 100 and a base
current of 30 A? 1. 30 A 2. 0.3 A 3. 3 mA 4. 3 MA
76. Which transistor region is very thin and lightly doped? A) the emitter region B) the
collector region C) the another region D) the base region
77. In a transistor which is the largest of all doped regions A) the emitter region B) the
collector region C) the gate region D) the base region
78. which region in a transistor is most heavily doped A) the emitter region B) the collector
region C) the gate region D) the base region
79. Emitter bias with two power supplies provides a A) very unstable Q point B) very stable
Q point C) large base voltage D) none of the above
80. For a transistor to function as an amplifier A) both the EB and CB junction must be
forward biased B) both the EB and CB junction must be reverse biased C) the EB junction
must be forward bias and the CB junction must be reverse biased D) the CB junction must be
forward bias and the EB junction must be reverse biased
81. For a typical transistor which two currents and nearly the same A) base current and
emitter current B) base current and collect or current C) collector current and emitter current
D) none of the above
82. The alpha dc of a transistor equals A) collector current divided by emitter current { the
ratio I/I is dc alpha (α) } B) base current divided by collector current C) emitter current divide
by collector current D) collector current divide by base current
8. When transistor is in saturation, A) Vce =VccB) Ic =0A C) Vce =0V D) Vce =1/2 Vcc
83. A transistor has the base current equal to 20 milliampere and collector current equal to
4.98 ampere ,Calculate emitter current. A)10A B) 20A C) 5AHint : (emitter current equal to
base current + collector current)D) 22.5 mA
84. A transistor has emitter current equal to 15 ampere and base current equal to 60
microampere ,calculate alpha DC. A) 0.996Hint :alpha dc equal to collector current divide by
emitter current, also collector current equal to emitter current – base current B) 200 C) 199 D)
5mA

85. Transistor has collector current 10 mA base current 50 microampere , calculate beta DC.
A) 0.996 B) 200 C) 199 D) 11.25 microampere
86. A transistor has alpha DC equal to 0.995, calculate beta DC A) 0.99 B) 0.97 C) 200 D)
199
87. A transistor is made up of three regions emitter, base and collector. A) base is a very thin
layer B) emitter is lightly doped region C) collector is the moderate in size D) all are true
88. In what operating region does the collector of a transistor act like a current source. A)
active region B) cutoff region C) saturation region E) the breakdown region
89. Which of the following biasing techniques produce the most unstable Q point. A) voltage
divider bias B) emitter bias C) collector bias D) Base bias
90. When the collector current in a transistor is zero ,the transistor is A) cut off B) saturated C)
operating in the breakdown region D) either b or c
91. For a transistor operating in the active region, A) collector current equal to beta DC x
base current B) Vcc has little or no effect on the value of collector current C) collector
current is controlled by Vcc D) both a and b
92. In a transistor amplifier ,what happens to the collector voltage ,when the collector current
increases? A) collector voltage increases B) collector voltage stays the same C) collector
voltage decreases D) this is impossible to determine
93. On the symbol of PNP transistor A) arrow points out on the emitter lead B) arrow points
out on the collector lead C) arrow points in on the base lead D) arrow points in on the emitter
lead
94. A BJT has A) only one PN junction B) three PN junctions C) no PN junction D) two PN
junctions
95. In a transistor which current is the largest A) collector current B) base current C) emitter
current D) diode current
96. In a transistor the line to which an arrowhead is marked is called A) emitter B) collector
C) base D) gate
97. If a emitter current in a transistor is 2mA , the collector current will be nearly A) 2mA B)
4mA C) 0.01mA D) 8mA
98. In a transistor with normal biasing, the A) emitter junction has high and collector junction
has low resistance B) emitter junction has low and collector junction has high resistance C)
both emitter and collector junctions have low resistance D) both emitter and collector
junctions have high resistance
99. The most commonly used transistor circuit arrangement is A) common base B) common
emitter C) common collector D) none of these
100. For transistor action, A) the base region must be very thin and lightly doped B) the
emitter junction should be forward biased and collector junction should be reverse baisedC)
the emitter should be heavily doped so that it can supply the required amount of majority
carriers D) all of these
101. The magnitude of leakage current in collector base junction with emitter open is A)
depends largely upon the emitter doping depends largely upon the emitter base junction bias
potential C) increases with the increase in temperature D) is generally greater in silicon than
germanium transistor
102. The silicon transistors are more widely used than germanium transistors because A) they
have smaller leakage current B) they have smaller depletion layers C) they have better ability
to dissipate heat D) they have larger current carrying capacity
103. A transistor when connected in CE mode has A) a low input resistance and low output
resistance B) a high input resistance and high output resistance C)high input resistance and
low output resistance D) a medium input resistance and high output resistance
104. A CE amplifier circuits are preferred over CB amplifier circuits because they have A)
lower amplification factor B) larger amplification factor C) high input resistance and low
output resistance D) none of these
105. The main current crossing the collector junction in a normally biased NPN transistor is
A) diffusion current B) drift current C) hole current D) equal to the base current
106. The emitter region in the PNP junction transistor is more heavily doped then the base
region so that A) the flow across the base region will be mainly because of electrons B) the
flow across the base region will be mainly because of holes C) recombination will be
increased in the base region D) base current will be high
107. For a given emitter current, the collector current will be higher if A) the recombination
rate in the base region were decreased B) the emitter region were more lightly doped C) the
minority carrier mobility in the base region were reduced D) the base region were made
wider
108. A small increase in the collector reverse bias will cause A) a large increase in emitter
current B) a large increase in collector current C) a large decrease in collector current D) very
small change in collector reverse saturation current
109. The input and output signals of a common emitter amplifier are A) always equal B) out
of phase C) always negative D) in phase
110. A transistor is connected in common base configuration has A) a low input resistance
and high output resistance B) high input resistance and low output resistance C) a low input
resistance and low output resistance D) high input resistance and high output resistance
111. A transistor is said to be in quiescent state when A) no signal is applied to the input B) it
is unbiased C) no currents are flowing D) emitter junction bias is just equal to collector
junction bias
112. The voltage gain of a transistor connected in common collector arrangement is A) equal
to 1 B) more than 10 C) more than 100 D) less than 1
113. The phase difference between the input and the output voltage of transistor in common
collector configuration is A) zero degree B) 180 degree C) 90 degree D) 270 degree
114. BC 147 transistor indicates that it is made of … A) germanium B) silicon C) carbon D)
none of these
115. Heat sink used with the transistor to A) increase the forward current B) decrease the
forward current C) compensate for excessive doping D) prevent excessive temperature rise
116. An amplifier should have A) high fidelity B) low noise C) stable operation D) all of the
above