2018
JEE Mains
MCQ
JEE Main 2018 (Online) 15th April Morning Slot
In a common emitter configuration with suitable bias, it is given that ${R_L}$ is the load resistance and ${R_{BE}}$ is small signal dynamic resistance (input side). Then, voltage gain, current gain and power gain are given, respectively, by :
$\beta $ is curret gain, ${{\rm I}_B},{{\rm I}_C}$ and ${{\rm I}_E}$ are respectively base, collector and emitter currents.
$\beta $ is curret gain, ${{\rm I}_B},{{\rm I}_C}$ and ${{\rm I}_E}$ are respectively base, collector and emitter currents.
A.
$\beta {{{R_L}} \over {{R_{BE}}}},{{\Delta {{\rm I}_C}} \over {\Delta {{\rm I}_B}}},{\beta ^2}{{{R_L}} \over {{R_{BE}}}}$
B.
$\beta {{{R_L}} \over {{R_{BE}}}},{{\Delta {{\rm I}_E}} \over {\Delta {{\rm I}_B}}},{\beta ^2}{{{R_L}} \over {{R_{BE}}}}$
C.
${\beta ^2}{{{R_L}} \over {{R_{BE}}}},{{\Delta {{\rm I}_C}} \over {\Delta {{\rm I}_E}}},{\beta ^2}{{{R_L}} \over {{R_{BE}}}}$
D.
${\beta ^2}{{{R_L}} \over {{R_{BE}}}},{{\Delta {{\rm I}_C}} \over {\Delta {{\rm I}_B}}},\beta {{{R_L}} \over {{R_{BE}}}}$
2017
JEE Mains
MCQ
JEE Main 2017 (Online) 9th April Morning Slot
The current gain of a common emitter amplifier is 69. If the emitter current is 7.0 mA, collector current is :
A.
9.6 mA
B.
6.9 mA
C.
0.69 mA
D.
69 mA
2017
JEE Mains
MCQ
JEE Main 2017 (Online) 8th April Morning Slot
The V-I characteristic of a diode is shown in the figure. The ratio of forward to reverse bias
resistance is :
A.
10
B.
10$-$6
C.
106
D.
100
2017
JEE Mains
MCQ
JEE Main 2017 (Online) 8th April Morning Slot
What is the conductivity of a semiconductor sale having electron concentration of $5 \times {10^{18}}\,\,{m^{ - 3}},$ hole concentration of $5 \times {10^{19}}\,\,{m^{ - 3}},$ electron mobility of 2.0 m2 V$-$1 s-1 and hole mobility of 0.01 m2 V$-$1 s$-$1 ?
(Take charge of electronas 1.6 $ \times $ 10 $-$19 c)
(Take charge of electronas 1.6 $ \times $ 10 $-$19 c)
A.
1.68 ($\Omega $-m)$-$1
B.
1.83 ($\Omega $-m)$-$1
C.
0.59 ($\Omega $-m)$-$1
D.
1.20 ($\Omega $-m)$-$1
2017
JEE Mains
MCQ
JEE Main 2017 (Offline)
In a common emitter amplifier circuit using an n-p-n transistor, the phase difference between the input and
the output voltages will be:
A.
180°
B.
45°
C.
90°
D.
135°
2016
JEE Mains
MCQ
JEE Main 2016 (Online) 10th April Morning Slot
To get an output of 1 from the circuit shown in figure the input must be :
A.
a = 0, b = 1, c = 0
B.
a = 1, b = 0, c = 0
C.
a = 1, b = 0, c = 1
D.
a = 0, b = 0, c = 1
2016
JEE Mains
MCQ
JEE Main 2016 (Online) 10th April Morning Slot
The ratio (R) of output resistance r0, and the input resistance ri in measurements of input and output characteristics of a transistor is typically in the range:
A.
R ~ 102 $-$ 103
B.
R ~ 1 $-$ 10
C.
R ~ 0.1 $-$ 0.01
D.
R ~ 0.1 $-$ 1.0
2016
JEE Mains
MCQ
JEE Main 2016 (Online) 10th April Morning Slot
A realistic graph depicting the variation of the reciprocal of input resistance in an input characteristics measurement in a commonemitter
transistor configuration is :
A.
B.
C.
D.
2016
JEE Mains
MCQ
JEE Main 2016 (Online) 9th April Morning Slot
An experiment is performed to determine the I - V characteristics of a Zener diode, which has a protective resistance of R = 100 $\Omega $, and a maximum power of dissipation rating of 1 W. The minimum voltage range of the DC source in the circuit is :
A.
0 $-$ 5 V
B.
0 $-$ 8 V
C.
0 $-$ 12 V
D.
0 $-$ 24 V
2016
JEE Mains
MCQ
JEE Main 2016 (Online) 9th April Morning Slot
An unknown transistor needs to be identified as a npn or pnp type. A multimeter, with + ve and − ve terminals, is used to measure resistance between different terminals of transistor. If terminal 2 is the base of the transistor then which of the following is correct for a pnp transistor ?
A.
+ ve termial 1, $-$ve terminal 2, resistance high
B.
+ ve termial 2, $-$ve terminal 1, resistance high
C.
+ ve termial 3, $-$ve terminal 2, resistance high
D.
+ ve termial 2, $-$ve terminal 3, resistance low
2016
JEE Mains
MCQ
JEE Main 2016 (Online) 9th April Morning Slot
The truth table given in fig. represents :
| A | B | Y |
|---|---|---|
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 1 |
A.
AND - Gate
B.
OR - Gate
C.
NAND - Gate
D.
NOR - Gate
2016
JEE Mains
MCQ
JEE Main 2016 (Offline)
The temperature dependence of resistance of $Cu$ and undoped $Si$ in the temperature range $300-400$ $K,$ is best described by :
A.
Linear increases for $Cu,$ exponential decrease of $Si.$
B.
Linear decrease for $Cu,$ linear decrease for $Si$
C.
Linear increase for $Cu,$ linear increase for $Si.$
D.
Linear increase for $Cu,$ exponential increase for $Si$
2016
JEE Mains
MCQ
JEE Main 2016 (Offline)
If $a, b, c, d$ are inputs to a gate and $x$ is its output, then, as per the following time graph, the gate is :
A.
$OR$
B.
$NAND$
C.
$NOT$
D.
$AND$
2016
JEE Mains
MCQ
JEE Main 2016 (Offline)
Identify the semiconductor devices whose characteristics are given below, in the order $(a), (b), (c), (d)$ :
A.
Simple diode, Zener diode, Solar cell, Light dependent resistance
B.
Zener diode, Simple diode, Light dependent resistance, Solar cell
C.
Solar cell, Light dependent resistance, Zener diode, simple diode
D.
Zener diode, Solar cell, simple diode, Light dependent resistance
2015
JEE Mains
MCQ
JEE Main 2015 (Offline)
A red $LED$ emits light at $0.1$ watt uniformly around it. The amplitude of the electric field of the light at a distance of $1$ $m$ from the diode is :
A.
$5.48$ $V/m$
B.
$7.75$ $V/m$
C.
$1.73$ $V/m$
D.
$2.45$ $V/m$
2014
JEE Mains
MCQ
JEE Main 2014 (Offline)
The forward biased diode connection is:
A.
B.
C.
D.
2014
JEE Mains
MCQ
JEE Main 2014 (Offline)
The current voltage relation of diode is given by ${\rm I} = \left( {{e^{100V/T}} - 1} \right)mA,$ where the applied voltage $V$ is in volts and the temperature $T$ is in degree kelvin. If a student makes an error measuring $ \pm 0.01\,V$ while measuring the current of $5$ $mA$ at $300$ $K,$ what will be the error in the value of current on $mA$?
A.
$0.2$ $mA$
B.
$0.02$ $mA$
C.
$0.5$ $mA$
D.
$0.05$ $mA$
2013
JEE Mains
MCQ
JEE Main 2013 (Offline)
The ${\rm I}$-$V$ characteristic of an $LED$ is
A.
B.
C.
D.
2013
JEE Mains
MCQ
JEE Main 2013 (Offline)
A diode detector is used to detect an amplitude modulated wave of $60\% $ modulation by using a condenser of capacity $250$ picofarad in parallel with a load resistance $100$ kilo $ohm.$ Find the maximum modulated frequency which could be detected by it.
A.
$10.62$ $MHz$
B.
$10.62$ $kHz$
C.
$5.31$ $MHz$
D.
$5.31$ $kHz$
2012
JEE Mains
MCQ
AIEEE 2012
Truth table for system of four $NAND$ gates as shown in figure is:
A.
B.
C.
D.
2010
JEE Mains
MCQ
AIEEE 2010
The combination of gates shown below yields
A.
OR gate
B.
NOT gate
C.
XOR gate
D.
NAND gate
2009
JEE Mains
MCQ
AIEEE 2009
The logic circuit shown below has the input waveforms $'A'$ and $'B'$ as shown. Pick out the correct output waveform.
Output is
A.
B.
C.
D.
2009
JEE Mains
MCQ
AIEEE 2009
A $p$-$n$ junction $(D)$ shown in the figure can act as a rectifier. An alternating current source $(V)$ is connected in the circuit.
The current $(I)$ in the resistor $(R)$ can be shown by :
A.
B.
C.
D.
2008
JEE Mains
MCQ
AIEEE 2008
In the circuit below, $A$ and $B$ represent two inputs and $C$ represents the output.
The circuit represents
A.
NOR gate
B.
AND gate
C.
NAND gate
D.
OR gate
2008
JEE Mains
MCQ
AIEEE 2008
A working transistor with its three legs marked $P,Q$ and $R$ is tested using a multi-meter. No conduction is found between $P$ and $Q$. By connecting the common (negative) terminal of the multi-meter to $R$ and the other (positive) terminal to $P$ or $Q,$ some resistance is seen on the multi-meter. Which of the following is true for the transistor?
A.
It is an $npn$ transistor with $R$ as base
B.
It is an $pnp$ transistor with $R$ as collector
C.
It is an $pnp$ transistor with $R$ as emitter
D.
It is an $npn$ transistor with $R$ as collector
2007
JEE Mains
MCQ
AIEEE 2007
If in a $p$-$n$ junction diode, a square input signal of $10$ $V$ is applied as shown
Then the output signal across ${R_L}$ will be
A.
B.
C.
D.
2007
JEE Mains
MCQ
AIEEE 2007
Carbon, silicon and germanium have four valence electrons each. At room temperature which one of the following statements is most appropriate ?
A.
The number of free electrons for conduction is significant only in $Si$ and $Ge$ but small in $C.$
B.
The number of free conduction electrons is significant in $C$ but small in $Si$ and $Ge.$
C.
The number of free conduction electrons is negligibly small in all the three.
D.
The number of free electrons for conduction is significant in all the three
2006
JEE Mains
MCQ
AIEEE 2006
If the lattice constant of this semiconductor is decreased, then which of the following is correct?
A.
All ${E_c},{E_g},{E_v}$ increase
B.
${E_c}$ and ${E_v}$ increase, but ${E_g}$ decreases
C.
${E_c}$ and ${E_v}$ decrease, but ${E_g}$ increases
D.
All ${E_c},{E_g},{E_v}$ decrease
2006
JEE Mains
MCQ
AIEEE 2006
In the following, which one of the diodes is reverse biased?
A.
B.
C.
D.
2006
JEE Mains
MCQ
AIEEE 2006
The circuit has two oppositively connected ideal diodes in parallel. What is the current following in the circuit?
A.
$1.71$ $A$
B.
$2.00$ $A$
C.
$2.31$ $A$
D.
$1.33$ $A$
2006
JEE Mains
MCQ
AIEEE 2006
In a common base mode of a transistor, the collector current is $5.488$ $mA$ for an emitter current of $5.60mA.$ The value of the base current amplification factor $\left( \beta \right)$ will be
A.
$49$
B.
$50$
C.
$51$
D.
$48$
2006
JEE Mains
MCQ
AIEEE 2006
If the ratio of the concentration of electrons to that of holes in a semiconductor is ${7 \over 5}$ and the ratio of currents is ${7 \over 4},$ then what is the ratio of their drift velocities?
A.
${5 \over 8}$
B.
${4 \over 5}$
C.
${5 \over 4}$
D.
${4 \over 7}$
2006
JEE Mains
MCQ
AIEEE 2006
A solid which is not transparent to visible light and whose conductivity increases with temperature is formed by
A.
Ionic bonding
B.
Covalent bonding
C.
Vander Waals bonding
D.
Metallic bonding
2005
JEE Mains
MCQ
AIEEE 2005
In a full wave rectifier circuit operating from $50$ $Hz$ mains frequency, the fundamental frequency in the ripple would be
A.
$25$ $Hz$
B.
$50$ $Hz$
C.
$70.7$ $Hz$
D.
$100$ $Hz$
2005
JEE Mains
MCQ
AIEEE 2005
In a common base amplifier, the phase difference between the input signal voltage and output voltage is
A.
$\pi $
B.
${\pi \over 4}$
C.
${\pi \over 2}$
D.
$0$
2005
JEE Mains
MCQ
AIEEE 2005
The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than $2480$ $nm$ is incident on it. The band gap in $(eV)$ for the semiconductor is
A.
$2.5$ $eV$
B.
$1.1$ $eV$
C.
$0.7$ $eV$
D.
$0.5$ $eV$
2004
JEE Mains
MCQ
AIEEE 2004
A piece of copper and another of germanium are cooled from room temperature to $77K,$ the resistance of
A.
copper increases and germanium decreases
B.
each of them decreases
C.
each of them increases
D.
copper decreases and germanium increases
2004
JEE Mains
MCQ
AIEEE 2004
The manifestation of band structure in solids is due to
A.
Bohr's correspondence principle
B.
Pauli's exclusion principle
C.
Heisenberg's uncertainty principle
D.
Boltzmann's law
2004
JEE Mains
MCQ
AIEEE 2004
When $p$-$n$ junction diode is forward biased then
A.
both the depletion region and barrier height are reduced
B.
the depletion region is widened and barrier height is reduced
C.
the depletion region is reduced and barrier height is increased
D.
both the depletion region and barrier height are increased
2004
JEE Mains
MCQ
AIEEE 2004
When $npn$ transistor is used as an amplifer
A.
electrons move from collector to base
B.
holes move from emitter to base
C.
electrons move from base to collector
D.
holes move from base to emitter
2004
JEE Mains
MCQ
AIEEE 2004
For a transistor amplifier in common emitter configuration for load impedance of $1k\,\Omega $ $\left( {{h_{fe}} = 50} \right.$ and $\left. {{h_{oe}} = 25} \right)$ the current gain is
A.
$-24.8$
B.
$-15.7$
C.
$-5.2$
D.
$-48.78$
2003
JEE Mains
MCQ
AIEEE 2003
The difference in the variation of resistance with temperature in a metal and a semiconductor arises essentially due to the difference in the
A.
crystal structure
B.
variation of the number of charge carries with temperature
C.
type of bonding
D.
variation of scattering mechanism with temperature
2003
JEE Mains
MCQ
AIEEE 2003
In the middle of the depletion layer of a reverse- biased $p$-$n$ junction, the
A.
electric field is zero
B.
potential is maximum
C.
electric field is maximum
D.
potential is zero
2003
JEE Mains
MCQ
AIEEE 2003
A strip of copper and another of germanium are cooled from room temperature to $80K.$ The resistance of
A.
each of these decreases
B.
copper strip increases and that of germanium decreases
C.
copper strip decreases and that of germanium increases
D.
each of these increases
2002
JEE Mains
MCQ
AIEEE 2002
By increasing the temperature, the specific resistance of a conductor and a semiconductor
A.
increases for both
B.
decreases for both
C.
increases, decreases
D.
decreases, increases
2002
JEE Mains
MCQ
AIEEE 2002
At absolute zero, Si acts as
A.
non-metal
B.
metal
C.
insulator
D.
none of these
2002
JEE Mains
MCQ
AIEEE 2002
The energy band gap is maximum in
A.
metals
B.
superconductors
C.
insulator
D.
semiconductor
2002
JEE Mains
MCQ
AIEEE 2002
The part of a transistor which is most heavily doped to produce large number of majority carriers is
A.
emmiter
B.
base
C.
collector
D.
can be any of the above three
2026
JEE Mains
Numerical
JEE Main 2026 (Online) 24th January Morning Shift
A voltage regulating circuit consisting of Zener diode, having break-down voltage of 10 V and maximum power dissipation of 0.4 W , is operated at 15 V . The approximate value of protective resistance in this circuit is $\_\_\_\_$ $\Omega$.
Correct Answer: 125
Explanation:
The series protective resistance limits the current flowing through the Zener diode so that it does not exceed the power rating.
The Zener diode maintains a constant voltage $\left(V_z\right)$ across load resistance $R_L$. The excess voltage from the source ( $V_{\text {in }}-V_z$ ) is dropped across the resistor $R_s$.
The Zener breakdown voltage $\mathrm{V}_{\mathrm{Z}}=10 \mathrm{~V}$
Maximum power dissipation $\mathrm{P}_{\text {max }}=0.4 \mathrm{~W}$
Using the power formula $\mathrm{P}=\mathrm{V} \times \mathrm{I}$.
$ I_{\max }=\frac{P_{\max }}{V_z} $
$\Rightarrow $ $ I_{\max }=\frac{0.4 \mathrm{~W}}{10 \mathrm{~V}}=0.04 \mathrm{~A} $
The resistor is connected in series with the Zener diode. According to Kirchhoff's Voltage Law (KVL), the sum of voltage drops must equal the supply voltage.
$V_{i n}=V_{R s}+V_z$
$\Rightarrow $ $V_{R s}=V_{i n}-V_z$
$\Rightarrow $ $ V_{R s}=15 \mathrm{~V}-10 \mathrm{~V}=5 \mathrm{~V} $
To protect the diode, we choose the resistance such that the current flowing through it does not exceed $\mathrm{I}_{\max }$.
$ \mathrm{R}_{\mathrm{s}}=\frac{\mathrm{V}_{\mathrm{Rs}}}{\mathrm{I}_{\mathrm{max}}} $
$\Rightarrow $ $\mathrm{R}_{\mathrm{s}}=\frac{5}{0.04} \Omega=125 \Omega$
2024
JEE Mains
Numerical
JEE Main 2024 (Online) 8th April Evening Shift
A potential divider circuit is connected with a dc source of $20 \mathrm{~V}$, a light emitting diode of glow in voltage $1.8 \mathrm{~V}$ and a zener diode of breakdown voltage of $3.2 \mathrm{~V}$. The length (PR) of the resistive wire is $20 \mathrm{~cm}$. The minimum length of PQ to just glow the LED is _________ $\mathrm{cm}$.
Correct Answer: 5
Explanation:
For minimum length of $P Q$,
$\begin{aligned} & \mathrm{V}_{\text {diodes }}=1.8+3.2=5 \mathrm{~V} \\ & \therefore \quad I_{P Q}=\frac{20}{20} \times 5 \\ & =5 \mathrm{~cm} \\ & \end{aligned}$