Semiconductor Electronics · Physics · NEET
MCQ (Single Correct Answer)
1
The current / in the circuit shown below is: (All diodes are ideal and identical)
NEET 2026
2
$$ \text { In the circuit shown below, the voltage appearing across the diode } D \text { will be of the form: } $$
NEET 2026
3
Two statements are given below:
A. When the forward bias voltage across a p-n junction diode increases above a certain threshold voltage, the diode current increases significantly.
B. This current is called reverse saturation current.
Choose the correct answer from the options given below:
NEET 2026
4
A full wave rectifier circuit with diodes $\left(D_1\right)$ and $\left(D_2\right)$ is shown in the figure. If input supply voltage $\mathrm{V}_{\text {in }}=220 \sin (100 \pi t)$ volt, then at $t=15 \mathrm{msec}$
NEET 2025
5
The output ( $Y$ ) of the given logic implementation is similar to the output of an/a ________ gate.
NEET 2025
6
The I-V characteristics shown above are exhibited by a
NEET 2024 (Re-Examination)
7
When the output of an OR gate is applied as input to a NOT gate, then the combination acts as a
NEET 2024 (Re-Examination)
8
The output Y for the inputs A and B of the given logic circuit is:
NEET 2024 (Re-Examination)
9
A logic circuit provides the output $$Y$$ as per the following truth table :
The expression of the output Y is :
NEET 2024
10
Consider the following statements A and B and identify the correct answer :
A. For a solar-cell, the I-V characteristics lies in the IV quadrant of the given graph.
B. In a reverse biased $$p n$$ junction diode, the current measured in $$(\mu \mathrm{A})$$, is due to majority charge carriers.
NEET 2024
11
$$ \text { The output ( } Y \text { ) of the given logic gate is similar to the output of an/a } $$
NEET 2024
12
On the basis of electrical conductivity, which one of the following material has the smallest resistivity?
NEET 2023 Manipur
13
The given circuit is equivalent to:
NEET 2023 Manipur
14
A p-type extrinsic semiconductor is obtained when Germanium is doped with:
NEET 2023 Manipur
15
The above figure shows the circuit symbol of a transistor. Select the correct statements given below:
(A) The transistor has two segments of p-type semiconductor separated by a segment of n-type semiconductor.
(B) The emitter is of moderate size and heavily doped.
(C) The central segment is thin and lightly doped.
(D) The emitter base junction is reverse biased in common emitter amplifier circuit.
NEET 2023 Manipur
16
Given below are two statements:
Statement I : Photovoltaic devices can convert optical radiation into electricity.
Statement II : Zener diode is designed to operate under reverse bias in breakdown region.
In the light of the above statements, choose the most appropriate answer from the options given below :
NEET 2023
17
A full wave rectifier circuit consists of two p-n junction diodes, a centre-tapped transformer, capacitor and a load resistance. Which of these components remove the ac ripple from the rectified output?
NEET 2023
18
For the following logic circuit, the truth table is:
NEET 2023
19
Identify the equivalent logic gate represented by the given circuit
NEET 2022 Phase 2
20
The incorrect statement about the property of a Zener diode is :
NEET 2022 Phase 2
21
The collector current in a common base amplifier using n-p-n transistor is 24 mA. If 80% of the electrons released by the emitter is accepted by the collector, then the base current is numerically :
NEET 2022 Phase 2
22
In the given circuits (a), (b) and (c), the potential drop across the two p-n junctions are equal in
NEET 2022 Phase 1
23
As the temperature increases, the electrical resistance
NEET 2022 Phase 1
24
In half wave rectification, if the input frequency is 60 Hz, then the output frequency would be
NEET 2022 Phase 1
25
The truth table for the given logic circuit is
NEET 2022 Phase 1
26
Consider the following statements (A) and (B) and identify the correct answer.
(A) A Zener diode is connected in reverse bias, when used as a voltage regulator.
(B) The potential barrier of p-n junction lies between 0.1 V to 0.3 V.
(A) A Zener diode is connected in reverse bias, when used as a voltage regulator.
(B) The potential barrier of p-n junction lies between 0.1 V to 0.3 V.
NEET 2021
27
The electron concentration in an n-type semiconductor is the same as hole concentration in a p-type semiconductor. An external field (electric) is applied across each of them. Compare the currents in them.
NEET 2021
28
For the given circuit, the input digital signals are applied at the terminals A, B and C. What would be the output at the terminal y?
NEET 2021
29
For transistor action, which of the following statements is correct?
NEET 2020 Phase 1
30
The increase in the width of the depletion region in a p-n junction diode is due to :
NEET 2020 Phase 1
31
For the logic circuit shown, the truth table is :
NEET 2020 Phase 1
32
The correct Boolean operation represented by the circuit diagram drawn is :
NEET 2019
33
For a p-type semiconductor, which of the following statements is true?
NEET 2019
34
In the circuit shown in the figure, the input
voltage Vi
is 20 V, VBE = 0 and VCE = 0. The
values of IB
, IC
and $$\beta $$ are given by
NEET 2018
35
In the combination of the following gates
the output Y can be written in terms of inputs
A and B as
NEET 2018
36
In a p-n junction diode, change in temperature
due to heating
NEET 2018
37
In a common emitter transistor amplifier the audio sgnal voltage across the collector is 3 V. The resistance of collector is 3 k$$\Omega $$. If current gain is 100 and the base resistance is 2 k$$\Omega $$, the voltage and power gain of the amplifier is
NEET 2017
38
Which one of the following represents forward bias diode ?
NEET 2017
39
The given electrical network is equivalent to
NEET 2017
40
The given circuit has two ideal diodes connected as shown in the figure. The current flowing through the resistance R1 will be
NEET 2016 Phase 2
41
What is the output Y in the following circuit, when all the three inputs A, B, C are first 0 and then 1 ?
NEET 2016 Phase 2
42
For CE transistor amplifier, the aufio signal voltage across the collector resistance of 2 k$$\Omega $$ is 4 V. If the current amplification factor of the transistor is 100 and the base resistance is 1 k$$\Omega $$, then the input signal voltage is
NEET 2016 Phase 2
43
To get output 1 for the following circuit, the correct choice for the input is
NEET 2016 Phase 1
44
A npn transistor is connected in common emitter configuration in a given amplifier. A load resistance of 800 $$\Omega $$ is connected in the collector circuit and the voltage frop across it is 0.8 V. If the current amplification factor is 0.96 and the input resistance of the circuit is 192 $$\Omega $$, the voltage gain and the power gain of the amplifier will respectively be
NEET 2016 Phase 1
45
Consider the junction diode as ideal. The value of current flowing through AB is
NEET 2016 Phase 1
46
The input signal given to a CE amplifier having a voltage gain of 150 is Vi = 2cos(15t + $${\pi \over 3}$$). The corresponding output signal will be
AIPMT 2015
47
In the given figure, a diode D is connected to an external resistance R = 100 $$\Omega $$ and an e.m.f. of 3.5 V. If the barrier potential developed across the diode is 0.5 V, the current in the citcuit will be
AIPMT 2015
48
Which logic gate is represented by the following combination of logic gates ?
AIPMT 2015 Cancelled Paper
49
If in a p-n junction, a square input signal of 10 V is applied, as shown,
then the output across RL will be
then the output across RL will be
AIPMT 2015 Cancelled Paper
50
The given graph represents V-I characteristic for a semiconductor device.
Which of the following statement is correct ?
Which of the following statement is correct ?
AIPMT 2014
51
The barrier potential of a p-n junction depends on
(1) type of semiconductor material
(2) amount of doping
(3) temperature
Which one of the following is correct ?
(1) type of semiconductor material
(2) amount of doping
(3) temperature
Which one of the following is correct ?
AIPMT 2014
52
The output from a NAND gate is divided into two in parallel and fed to another NAND gate. The resulting gate is a
NEET 2013 (Karnataka)
53
One way in which the operation of a n-p-n transistor differs from that of a p-n-p
NEET 2013 (Karnataka)
54
In an unbiased p-n junction, holes diffuse from the p-region to n-region because of
NEET 2013 (Karnataka)
55
In a common emitter (CE) amplifier having a voltage gain G, the transistor used has transconductance 0.03 mho and current gain 25. If the above transistor is replaced with another one with transconductance 0.02 mho and current gain 20, the voltage gain will be
NEET 2013
56
The output (X) of the logic circuit shown ion figure will be
NEET 2013
57
In a n-type semiconductor, which of the following statement is true.
NEET 2013
58
The input resistance of a silicon transistor is 100 $$\Omega $$. Base current is changed by 40 $$\mu $$A which results in a change in collector current by 2 mA. This transistor is used as a common emitter amplifier with a load resistance of 4 k$$\Omega $$. The voltage gain of the amplifier is
AIPMT 2012 Mains
59
To get an output Y= 1 in given circuit which of the following input will be correct ?
AIPMT 2012 Mains
60
In a CE transistor amplifier, the audio signal voltage across the collector resistance of 2 k$$\Omega $$ is 2 V. If the base resistance is 1 k$$\Omega $$ and the current amplification of the transistor is 100, the input signal voltage is
AIPMT 2012 Prelims
61
Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is
AIPMT 2012 Prelims
62
The figure shows a logic circuit with two inputs A and B and the output C. The voltage wave forms across A, B and C are as given. The logic circuit gate is
AIPMT 2012 Prelims
63
C and Si both have same lattice structure; having 4 bonding electrons in each. However, C is insulator where as Si is intrinsic semiconductor. This is because
AIPMT 2012 Prelims
64
Transfer characteristics [output voltage (V0) vs input voltage (Vi)] for a base biased transistor in CE configuration is as shown in the figure. For using transistor as a switch, it is used
AIPMT 2012 Prelims
65
A Zener diode, having breakdown voltage equal to 15 V, is used in a voltage regulator circuit shown in figure. The current through the diode is
AIPMT 2011 Mains
66
In the following figure, the diodes which are forward biased, are
AIPMT 2011 Mains
67
Pure Si at 500 K has equal number of electron (ne) and hole (nh) concentrations of 1.5 $$ \times $$ 1016 m$$-$$3. Doping by indium increases nh to 4.5 $$ \times $$ 1022 m$$-$$3. The doped semiconductor is of
AIPMT 2011 Mains
68
Symbolic representation of four logic gates are shown as
Pick out which ones are for AND, NAND and NOT gates, respectively
Pick out which ones are for AND, NAND and NOT gates, respectively
AIPMT 2011 Prelims
69
A transistor is operated in common emitter configuration at VC = 2 V such that a change in the base current from 100 $$\mu $$A to 300 $$\mu $$A produces a change in the collector current from 10 mA to 20 mA. The current gain is
AIPMT 2011 Prelims
70
If a small amount of antimony is added to germanium crystal
AIPMT 2011 Prelims
71
In forward biasing of the p-n junction
AIPMT 2011 Prelims
72
The following figure shows a logic gate circuit with two inputs A and B and the output Y. The voltage waveforms of A, B and Y are as given.
The logic gate is
The logic gate is
AIPMT 2010 Mains
73
For transistor action
(1) Base, emitter and collector regions should have similar size and doping concentrations.
(2) The base region must be vety thin and lightly doped.
(3) The emitter-base junction is forward biased and base-collector junction is reverse biased.
(4) Both the emitter-base junction as well as the base-collector junction are forward biased.
Which one of the following pairs of statements is correct?
(1) Base, emitter and collector regions should have similar size and doping concentrations.
(2) The base region must be vety thin and lightly doped.
(3) The emitter-base junction is forward biased and base-collector junction is reverse biased.
(4) Both the emitter-base junction as well as the base-collector junction are forward biased.
Which one of the following pairs of statements is correct?
AIPMT 2010 Mains
74
To get an output Y = 1 in given circuit which of the following input will be correct ?
AIPMT 2010 Prelims
75
A common emitter amplifier has a voltage gain of 50, an input impedance of 100 $$\Omega $$ and an output impedance of 200 $$\Omega $$. The power gain of the amplifier is
AIPMT 2010 Prelims
76
The device that can act as a complete electronic circuit is
AIPMT 2010 Prelims
77
Which one of the following bonds produces a solid that reflects light in the visible region and whose electrical conductivity decreases with temperature and has high melting point ?
AIPMT 2010 Prelims
78
Which one of the following statement is false ?
AIPMT 2010 Prelims
79
A transistor is operated in common-emitter configuration at VC = 2V such that a change in the base current from 100 $$\mu $$A to 200 $$\mu $$A produces a change in the collector current from 5 mA to 10 mA. The current gain is
AIPMT 2009
80
A p-n photodiode is fabricated from a semiconductor with a band gap of 2.5 eV. It can detect a signal of wavelength
AIPMT 2009
81
The symbolic representation of four logic gates are given below
The logic symbols for OR, NOT and NAND gates are respectively
The logic symbols for OR, NOT and NAND gates are respectively
AIPMT 2009
82
Sodium has body centred packing. Distance between two nearest atoms is 3.7 $$\mathop A\limits^ \circ $$. The lattice parameter is
AIPMT 2009
83
If the lattice parameter for a crystalline structure is 3.6 $$\mathop A\limits^ \circ $$, then the atomic radius in fcc crystal is
AIPMT 2008
84
The voltage gain of an amplifier with 9% negative feedback is 10. The voltage gain without feedback will be
AIPMT 2008
85
A p-n photodiode is made of a material with a band gap of 2.0 eV. The minimum frequency of the radiation that can be absorbed by the material is nearly
AIPMT 2008
86
Which one of the following represents forward bias diode ?
AIPMT 2007
87
In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is
AIPMT 2007
88
For a cubic crystal structure which one of the following relations indicating the cell characteristics is correct ?
AIPMT 2007
89
In the following circuit, the output Y for all possible inputs A and B is expressed by the truth table.
AIPMT 2007
90
Which one of the following represents forward bias diode ?
AIPMT 2006
91
The following figure shows a logic gate circuit with two inputs A and B and the output C.
The voltage waveforms of A, B and C are as shown below.
The logic circuit gate is
The voltage waveforms of A, B and C are as shown below.
The logic circuit gate is
AIPMT 2006
92
A transistor is operated in common emitter configuration at constant collector voltage VC = 1.5 V such that a change in the base current from 100 $$\mu $$A to 150 $$\mu $$A profuces a change in the collector current from 5 mA to 10 mA. The current gain $$\beta $$ is
AIPMT 2006
93
In a p-n junction photo cell, the value of the photo-electromotive force profuced by monochromatic light is proportional to
AIPMT 2005
94
Carbon, silicon and germanium atoms have four valence electrons each. Their valence and conduction bands are separated by energy band gaps represented by (Eg)C, (Eg)si and (Eg)Ge respectively. Which one of the following relationships is true in their case?
AIPMT 2005
95
Application of a forward bias to a p-n junction
AIPMT 2005
96
Zener diode is used for
AIPMT 2005
97
Choose the only false statement from the following.
AIPMT 2005
98
Copper has face centered cubic (fcc) lattice with interatomic spacing equal to 2.54 $$\mathop A\limits^ \circ $$. The value of lattice constant for this lattice is
AIPMT 2005
99
In semiconductors at a room temperature
AIPMT 2004
100
The peak voltage in the output of a half wave diode rectifier fed with a sinusoidal signal without filter is 10 V. The d.c. component of the output voltage is
AIPMT 2004
101
Of the diodes shown in the following diagrams, which one is reverse biased ?
AIPMT 2004
102
The output of OR gate is 1
AIPMT 2004
103
A n-p-n transistor conducts when
AIPMT 2003
104
Reverse bias applied to a junction diode
AIPMT 2003
105
If a full wave rectifier circuit is operating from 50 Hz mains, the fundamental frequency in the ripple will be
AIPMT 2003
106
Barrier potential of a p-n junction diode does not depened on
AIPMT 2003
107
For a transistor $${{{I_C}} \over {{I_E}}}$$ = 0.96, then current gain for common emitter is
AIPMT 2002
108
For the given circuit of p-n junction diode which is correct
AIPMT 2002
109
The given truth table is for which logic gate
$$\matrix{ A & B & Y \cr 1 & 1 & 0 \cr 0 & 1 & 1 \cr 1 & 0 & 1 \cr 0 & 0 & 1 \cr } $$
$$\matrix{ A & B & Y \cr 1 & 1 & 0 \cr 0 & 1 & 1 \cr 1 & 0 & 1 \cr 0 & 0 & 1 \cr } $$
AIPMT 2002
110
Number of atom per unit cell in B.C.C.
AIPMT 2002
111
In a p-n junction
AIPMT 2002
112
The given truth table is for which logic gate
$$\matrix{ A & B & Y \cr 1 & 1 & 0 \cr 0 & 1 & 1 \cr 1 & 0 & 1 \cr 0 & 0 & 1 \cr } $$
$$\matrix{ A & B & Y \cr 1 & 1 & 0 \cr 0 & 1 & 1 \cr 1 & 0 & 1 \cr 0 & 0 & 1 \cr } $$
AIPMT 2001
113
The current in the circuit will be
AIPMT 2001
114
For a common base circuit if $${{{I_C}} \over {{I_E}}}$$ = 0.98 then current gain for common emitter circuit will be
AIPMT 2001
115
From the following diode circuit, which diode is in forward biased condition
AIPMT 2000
116
The correct relation for $$\alpha $$, $$\beta $$ for a transistor
AIPMT 2000
117
The cations and anions are arranged in alternate form in
AIPMT 2000