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Semiconductor Electronics

114 Questions
All Exams NEET AIIMS
2013 NEET MCQ
NEET 2013 (Karnataka)
In an unbiased p-n junction, holes diffuse from the p-region to n-region because of
A.
The attraction of free electrons of n-region.
B.
The higher hole concentration in p-region than that in n-region.
C.
The higher concentration of electrons in the n-region than that in the p-region.
D.
The potential difference across the p-n junction.
2013 NEET MCQ
NEET 2013
In a n-type semiconductor, which of the following statement is true.
A.
Holes are minority carries and pentavalent atoms are dopants.
B.
Holes are majority carries and trivalent atoms are dopants.
C.
Electrons are majority carries and trivalent atoms are dopants.
D.
Electrons are minority carriers and pentavalent atoms are dopants.
2013 NEET MCQ
NEET 2013
The output (X) of the logic circuit shown ion figure will be

NEET 2013 Physics - Semiconductor Electronics Question 96 English
A.
X = A . B
B.
X = $\overline {A + B} $
C.
X = $\overline {\overline A } .\overline {\overline B } $
D.
X = $\overline {A.B} $
2013 NEET MCQ
NEET 2013
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
A.
${1 \over 3}G$
B.
${5 \over 4}G$
C.
${2 \over 3}G$
D.
1.5G
2012 NEET MCQ
AIPMT 2012 Mains
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
A.
2000
B.
3000
C.
4000
D.
1000
2012 NEET MCQ
AIPMT 2012 Mains
To get an output Y= 1 in given circuit which of the following input will be correct ?

AIPMT 2012 Mains Physics - Semiconductor Electronics Question 86 English
A.
A $ \to $ 1,  B $ \to $ 0,  C $ \to $ 0
B.
A $ \to $ 1,  B $ \to $ 0,  C $ \to $ 1
C.
A $ \to $ 1,  B $ \to $ 1,  C $ \to $ 0
D.
A $ \to $ 0,  B $ \to $ 1,  C $ \to $ 0
2012 NEET MCQ
AIPMT 2012 Prelims
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
A.
In case of C the valence band is not completely filled at absolute zero temperature.
B.
In case of C the conduction band is partly filled even at absolute zero temperature.
C.
The four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si they lie in the third.
D.
The four bonding electrons in the case of C lie in the third orbit , whereas for Si they lie in the fourth orbit.
2012 NEET MCQ
AIPMT 2012 Prelims
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 Physics - Semiconductor Electronics Question 89 English
A.
in region III
B.
both in region (I) and (III)
C.
in region II
D.
in region I
2012 NEET MCQ
AIPMT 2012 Prelims
Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is

AIPMT 2012 Prelims Physics - Semiconductor Electronics Question 92 English
A.
0.75 A
B.
zero
C.
0.25 A
D.
0.5 A
2012 NEET MCQ
AIPMT 2012 Prelims
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 Physics - Semiconductor Electronics Question 88 English
A.
OR gate
B.
NOR gate
C.
AND gate
D.
NAND gate
2012 NEET MCQ
AIPMT 2012 Prelims
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
A.
0.1 V
B.
1.0 V
C.
1 mV
D.
10 mV
2011 NEET MCQ
AIPMT 2011 Mains
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
A.
p-type having electron concentration ne = 5 $ \times $ 109 m$-$3
B.
n-type with electron concentration ne = 5 $ \times $ 1022 m$-$3
C.
p-type with electron concentration ne = 2.5 $ \times $ 1010 m$-$3
D.
n-type with electron concentration ne = 2.5 $ \times $ 1023 m$-$3
2011 NEET MCQ
AIPMT 2011 Mains
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 Physics - Semiconductor Electronics Question 80 English
A.
5 mA
B.
10 mA
C.
15 mA
D.
20 mA
2011 NEET MCQ
AIPMT 2011 Mains
In the following figure, the diodes which are forward biased, are

AIPMT 2011 Mains Physics - Semiconductor Electronics Question 79 English
A.
(A), (B) and (D)
B.
(C) only
C.
(C) and (A)
D.
(B) and (D)
2011 NEET MCQ
AIPMT 2011 Prelims
In forward biasing of the p-n junction
A.
the positive terminal of the battery is connected to p-side and the depletion region becomes thick.
B.
the positive terminal of the battery is connected to n-side and the depletion region becomes thin.
C.
the positive terminal of the battery is connected to n-side and the depletion region becomes thick.
D.
the positive terminal of the battery is connected to p-side and the depletion region becomes thin.
2011 NEET MCQ
AIPMT 2011 Prelims
If a small amount of antimony is added to germanium crystal
A.
it becomes a p-type semiconductor
B.
the antimony becomes an acceptor atom
C.
there will be more free electrons than holes in the semiconductor
D.
its resistance is increased
2011 NEET MCQ
AIPMT 2011 Prelims
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
A.
50
B.
75
C.
100
D.
25
2011 NEET MCQ
AIPMT 2011 Prelims
Symbolic representation of four logic gates are shown as

AIPMT 2011 Prelims Physics - Semiconductor Electronics Question 82 English

Pick out which ones are for AND, NAND and NOT gates, respectively
A.
(ii), (iii) and (iv)
B.
(iii), (ii) and (i)
C.
(iii), (ii) and (iv)
D.
(ii), (iv) and (iii)
2010 NEET MCQ
AIPMT 2010 Mains
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.

AIPMT 2010 Mains Physics - Semiconductor Electronics Question 73 English

The logic gate is
A.
NOR gate
B.
OR gate
C.
AND gate
D.
NAND gate
2010 NEET MCQ
AIPMT 2010 Mains
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?
A.
(4) and (1)
B.
(1) and (2)
C.
(2) and (3)
D.
(3) and (4)
2010 NEET MCQ
AIPMT 2010 Prelims
To get an output Y = 1 in given circuit which of the following input will be correct ?

AIPMT 2010 Prelims Physics - Semiconductor Electronics Question 85 English
A.
A $ \to $ 1,  B $ \to $ 0,  C $ \to $ 0
B.
A $ \to $ 1,  B $ \to $ 0,  C $ \to $ 1
C.
A $ \to $ 1,  B $ \to $ 1,  C $ \to $ 0
D.
A $ \to $ 0,  B $ \to $ 1,  C $ \to $ 0
2010 NEET MCQ
AIPMT 2010 Prelims
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
A.
500
B.
1000
C.
1250
D.
50
2010 NEET MCQ
AIPMT 2010 Prelims
Which one of the following statement is false ?
A.
Pure Si doped with trivalent impurities gives a p-type semiconductor.
B.
Majority carries in a n-type semiconductor are holes.
C.
Minority carries in a p-type semiconductor are electrons.
D.
The resistance of intrinisic semiconductor decreases with increase of temperature.
2010 NEET MCQ
AIPMT 2010 Prelims
The device that can act as a complete electronic circuit is
A.
junction diode
B.
integrated circuit
C.
junction transistor
D.
zener diode
2010 NEET MCQ
AIPMT 2010 Prelims
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 ?
A.
metallic bonding
B.
van der Waal's bonding
C.
ionic bonding
D.
covalent bonding
2009 NEET MCQ
AIPMT 2009
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
A.
100
B.
150
C.
50
D.
75
2009 NEET MCQ
AIPMT 2009
A p-n photodiode is fabricated from a semiconductor with a band gap of 2.5 eV. It can detect a signal of wavelength
A.
4000 nm
B.
6000 nm
C.
4000 $\mathop A\limits^ \circ $
D.
6000 $\mathop A\limits^ \circ $
2009 NEET MCQ
AIPMT 2009
Sodium has body centred packing. Distance between two nearest atoms is 3.7 $\mathop A\limits^ \circ $. The lattice parameter is
A.
4.3 $\mathop A\limits^ \circ $
B.
3.0 $\mathop A\limits^ \circ $
C.
8.6 $\mathop A\limits^ \circ $
D.
6.8 $\mathop A\limits^ \circ $
2009 NEET MCQ
AIPMT 2009
The symbolic representation of four logic gates are given below

AIPMT 2009 Physics - Semiconductor Electronics Question 70 English

The logic symbols for OR, NOT and NAND gates are respectively
A.
(iv), (i), (iii)
B.
(iv), (ii), (i)
C.
(i), (iii), (iv)
D.
(iii), (iv), (ii)
2008 NEET MCQ
AIPMT 2008
The voltage gain of an amplifier with 9% negative feedback is 10. The voltage gain without feedback will be
A.
1.25
B.
100
C.
90
D.
10
2008 NEET MCQ
AIPMT 2008
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
A.
1 $ \times $ 1014 Hz
B.
20 $ \times $ 1014 Hz
C.
10 $ \times $ 1014 Hz
D.
5 $ \times $ 1014 Hz
2008 NEET MCQ
AIPMT 2008
If the lattice parameter for a crystalline structure is 3.6 $\mathop A\limits^ \circ $, then the atomic radius in fcc crystal is
A.
2.92 $\mathop A\limits^ \circ $
B.
1.27 $\mathop A\limits^ \circ $
C.
1.81 $\mathop A\limits^ \circ $
D.
2.10 $\mathop A\limits^ \circ $
2007 NEET MCQ
AIPMT 2007
For a cubic crystal structure which one of the following relations indicating the cell characteristics is correct ?
A.
a $ \ne $ b $ \ne $ c  and  $\alpha $ = $\beta $ = $\gamma $ = 90o
B.
a = b = c  and  $\alpha $ $ \ne $ $\beta $ $ \ne $ $\gamma $ = 90o
C.
a = b = c  and  $\alpha $ = $\beta $ = $\gamma $ = 90o
D.
a $ \ne $ b $ \ne $ c  and  ;$\alpha $ $ \ne $ $\beta $ $ \ne $  and  $\gamma $ = 90o
2007 NEET MCQ
AIPMT 2007
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 Physics - Semiconductor Electronics Question 62 English
A.
an insulator
B.
a metal
C.
an n-type semiconductor
D.
a p-type semiconductor.
2007 NEET MCQ
AIPMT 2007
Which one of the following represents forward bias diode ?
A.
AIPMT 2007 Physics - Semiconductor Electronics Question 111 English Option 1
B.
AIPMT 2007 Physics - Semiconductor Electronics Question 111 English Option 2
C.
AIPMT 2007 Physics - Semiconductor Electronics Question 111 English Option 3
D.
AIPMT 2007 Physics - Semiconductor Electronics Question 111 English Option 4
2007 NEET MCQ
AIPMT 2007
In the following circuit, the output Y for all possible inputs A and B is expressed by the truth table.

AIPMT 2007 Physics - Semiconductor Electronics Question 64 English
A.
$\matrix{ A & B & Y \cr 0 & 0 & 1 \cr 0 & 1 & 1 \cr 1 & 0 & 1 \cr 1 & 1 & 0 \cr } $
B.
$\matrix{ A & B & Y \cr 0 & 0 & 1 \cr 0 & 1 & 0 \cr 1 & 0 & 0 \cr 1 & 1 & 0 \cr } $
C.
$\matrix{ A & B & Y \cr 0 & 0 & 0 \cr 0 & 1 & 1 \cr 1 & 0 & 1 \cr 1 & 1 & 1 \cr } $
D.
$\matrix{ A & B & Y \cr 0 & 0 & 0 \cr 0 & 1 & 0 \cr 1 & 0 & 0 \cr 1 & 1 & 1 \cr } $
2006 NEET MCQ
AIPMT 2006
The following figure shows a logic gate circuit with two inputs A and B and the output C.

AIPMT 2006 Physics - Semiconductor Electronics Question 61 English 1

The voltage waveforms of A, B and C are as shown below.

AIPMT 2006 Physics - Semiconductor Electronics Question 61 English 2

The logic circuit gate is
A.
OR gate
B.
AND gate
C.
NAND gate
D.
NOR gate
2006 NEET MCQ
AIPMT 2006
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
A.
50
B.
67
C.
75
D.
100
2006 NEET MCQ
AIPMT 2006
Which one of the following represents forward bias diode ?
A.
AIPMT 2006 Physics - Semiconductor Electronics Question 34 English Option 1
B.
AIPMT 2006 Physics - Semiconductor Electronics Question 34 English Option 2
C.
AIPMT 2006 Physics - Semiconductor Electronics Question 34 English Option 3
D.
AIPMT 2006 Physics - Semiconductor Electronics Question 34 English Option 4
2005 NEET MCQ
AIPMT 2005
In a p-n junction photo cell, the value of the photo-electromotive force profuced by monochromatic light is proportional to
A.
The barrier voltage at the p-n junction.
B.
The intensity of the light falling on the cell.
C.
The frequency of the light falling on the cell.
D.
The voltage applied at the p-n junction.
2005 NEET MCQ
AIPMT 2005
Choose the only false statement from the following.
A.
In conductors the valence and conduction bands overlap.
B.
Substances with energy gap of the order of 10 eV are insulators.
C.
The resistivity of a semiconductor increases with increase in temperature.
D.
The conductivity of a semiconductor increases with increase in temperature.
2005 NEET MCQ
AIPMT 2005
Zener diode is used for
A.
amplification
B.
rectification
C.
stabilisation
D.
producing oscillations in an oscillator.
2005 NEET MCQ
AIPMT 2005
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
A.
2.54 $\mathop A\limits^ \circ $
B.
3.59 $\mathop A\limits^ \circ $
C.
1.27 $\mathop A\limits^ \circ $
D.
5.08 $\mathop A\limits^ \circ $
2005 NEET MCQ
AIPMT 2005
Application of a forward bias to a p-n junction
A.
widens the depletion zone
B.
increases the potential difference across the depletion zone
C.
increases the number of donors on the n side
D.
decreases the electric field in the depletion zone.
2005 NEET MCQ
AIPMT 2005
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?
A.
(Eg)C > (Eg)Si
B.
(Eg)C < (Eg)Si
C.
(Eg)C = (Eg)Si
D.
(Eg)C < (Eg)Ge.
2004 NEET MCQ
AIPMT 2004
In semiconductors at a room temperature
A.
the valence band is partially empty and the conduction band is partially filled
B.
the valence band is completely filled and the conduction band is partially filled
C.
the valence band is completely filled
D.
the conduction band is completely empty
2004 NEET MCQ
AIPMT 2004
The output of OR gate is 1
A.
if both inputs are zero
B.
if either or both inputs are 1
C.
only if both inputs are 1
D.
if either inputs is zero
2004 NEET MCQ
AIPMT 2004
Of the diodes shown in the following diagrams, which one is reverse biased ?
A.
AIPMT 2004 Physics - Semiconductor Electronics Question 50 English Option 1
B.
AIPMT 2004 Physics - Semiconductor Electronics Question 50 English Option 2
C.
AIPMT 2004 Physics - Semiconductor Electronics Question 50 English Option 3
D.
AIPMT 2004 Physics - Semiconductor Electronics Question 50 English Option 4
2004 NEET MCQ
AIPMT 2004
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
A.
(10/$\sqrt 2 $) V
B.
$\left( {{{10} \over \pi }} \right)V$
C.
10 V
D.
(20/$\pi $) V
2003 NEET MCQ
AIPMT 2003
If a full wave rectifier circuit is operating from 50 Hz mains, the fundamental frequency in the ripple will be
A.
25 Hz
B.
50 Hz
C.
70.7 Hz
D.
100 Hz