2021
JEE Mains
Numerical
JEE Main 2021 (Online) 20th July Evening Shift
A zener diode having zener voltage 8 V and power dissipation rating of 0.5 W is connected across a potential divider arranged with maximum potential drop across zener diode is as shown in the diagram. The value of protective resistance Rp is .................... $\Omega$.
Correct Answer: 192
Explanation:
P = Vi
0.5 = 8i
i = ${1 \over {16}}$A
E = 20 = 8 + i Rp
Rp = 12 $\times$ 16 = 192$\Omega$
0.5 = 8i
i = ${1 \over {16}}$A
E = 20 = 8 + i Rp
Rp = 12 $\times$ 16 = 192$\Omega$
2021
JEE Mains
Numerical
JEE Main 2021 (Online) 20th July Evening Shift
For the forward biased diode characteristics shown in the figure, the dynamic resistance at ID = 3 mA will be __________ $\Omega$.
Correct Answer: 25
Explanation:
${R_d} = {{dV} \over {di}} = {1 \over {{{di} \over {dv}}}} = {1 \over {{{5 - 1 \times {{10}^{ - 3}}} \over {0.75 - 0.65}}}}$
$ = {{100} \over 4} = 25\Omega $
$ = {{100} \over 4} = 25\Omega $
2021
JEE Mains
Numerical
JEE Main 2021 (Online) 18th March Evening Shift
The typical output characteristics curve for a transistor working in the common-emitter configuration is shown in the figure.
The estimated current gain from the figure is __________.
The estimated current gain from the figure is __________.
Correct Answer: 200
Explanation:
For common emitter configuration
$\beta $ = ${{\Delta {I_C}} \over {\Delta {I_B}}} = {{\left( {4 - 2} \right)\,mA} \over {\left( {20 - 10} \right)\,\mu A}}$
= ${2 \over {10}} \times {{{{10}^{ - 3}}} \over {{{10}^{ - 6}}}}$ = 200
$\beta $ = ${{\Delta {I_C}} \over {\Delta {I_B}}} = {{\left( {4 - 2} \right)\,mA} \over {\left( {20 - 10} \right)\,\mu A}}$
= ${2 \over {10}} \times {{{{10}^{ - 3}}} \over {{{10}^{ - 6}}}}$ = 200
2021
JEE Mains
Numerical
JEE Main 2021 (Online) 18th March Morning Shift
An npn transistor operates as a common emitter amplifier with a power gain of 106. The input circuit resistance is 100$\Omega$ and the output load resistance is 10 K$\Omega$. The common emitter current gain '$\beta$' will be ________. (Round off to the Nearest Integer).
Correct Answer: 100
Explanation:
Power gain = 106
Input resistance = 100$\Omega$
Output load resistance = 10K$\Omega$
Power gain = ${\beta^2} \times {{{r_{out}}} \over {{R_{in}}}}$
$ \Rightarrow $ ${10^6} = {\beta ^2} \times {{10 \times {{10}^3}} \over {100}}$
$ \Rightarrow $ $\beta$2 = 104
$ \Rightarrow $ $\beta$ = 100
Input resistance = 100$\Omega$
Output load resistance = 10K$\Omega$
Power gain = ${\beta^2} \times {{{r_{out}}} \over {{R_{in}}}}$
$ \Rightarrow $ ${10^6} = {\beta ^2} \times {{10 \times {{10}^3}} \over {100}}$
$ \Rightarrow $ $\beta$2 = 104
$ \Rightarrow $ $\beta$ = 100
2021
JEE Mains
Numerical
JEE Main 2021 (Online) 16th March Morning Shift
The value of power dissipated across the zener diode (Vz = 15V) connected in the circuit as shown in the figure is x $\times$ 10$-$1 watt.
The value of x, to the nearest integer, is __________.
The value of x, to the nearest integer, is __________.
Correct Answer: 5
Explanation:
$i = {7 \over {35}} = {1 \over 5}A$
${i_1} = {{15} \over {90}} = {1 \over 6}A$
${i_2} = i - {i_1}$
${i_2} = {1 \over 5} - {1 \over 6}$
${i_2} = {1 \over {30}}A$
Power across diode; P = V2 i2
$P = 15 \times {1 \over {30}}$
P = 0.5 W
$ \therefore $ P = 5 $\times$ 10$-$1 W
2021
JEE Mains
Numerical
JEE Main 2021 (Online) 16th March Morning Shift
In the logic circuit shown in the figure, if input A and B are 0 to 1 respectively, the output at Y would be 'x'.
The value of x is ____________.
The value of x is ____________.
Correct Answer: 0
Explanation:
2021
JEE Mains
Numerical
JEE Main 2021 (Online) 26th February Evening Shift
The zener diode has a Vz = 30V. The current passing through the diode for the following circuit is ________ mA.
Correct Answer: 9
Explanation:
$I = {{90 - 30} \over 4} = 15mA$
${I_1} = {{30} \over {5K\Omega }} = 6mA$
${I_2} = 15mA - 6mA = 9mA$
2021
JEE Mains
Numerical
JEE Main 2021 (Online) 26th February Morning Shift
The circuit contains two diodes each with a forward resistance of 50$\Omega$ and with infinite reverse resistance. If the battery voltage is 6V, the current through the 120$\Omega$ resistance is ____________ mA.
Correct Answer: 20
Explanation:
Given, forward resistance, R1 = 50 $\Omega$
Reverse resistance, R2 = infinity
Battery voltage = 6V
According to circuit diagram,
In this case, diode D1 is forward biased, whereas diode D2 is reverse biased.
So, D2 will act as open circuit.
$6 - 50I - 130I - 120I = 0$
$ \Rightarrow 6 = 300I$
$ \Rightarrow I = {6 \over {300}} = {1 \over {50}}$
$ = {2 \over {100}} = 0.02$ A = 20 mA
Hence, current through 120 $\Omega$ = 20 mA
2021
JEE Mains
Numerical
JEE Main 2021 (Online) 24th February Morning Shift
In connection with the circuit drawn below, the value of current flowing through 2 k$\Omega$ resistor is _________ $\times$ 10$-$4 A.
Correct Answer: 25
Explanation:
Given, resistance, R = 2 k$\Omega$ = 2 $\times$ 103 $\Omega$
In Zener breakdown,
$i = {V \over R} = {5 \over {2 \times {{10}^3}}} = 2.5 \times {10^{ - 3}}$
$\because$ $x \times {10^{ - 4}} = 25 \times {10^{ - 4}}$
$\therefore$ x = 25
In Zener breakdown,
$i = {V \over R} = {5 \over {2 \times {{10}^3}}} = 2.5 \times {10^{ - 3}}$
$\because$ $x \times {10^{ - 4}} = 25 \times {10^{ - 4}}$
$\therefore$ x = 25
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 6th September Morning Slot
Identify the correct output signal Y in the given combination of gates (as shown) for the given
inputs A and B.
A.
B.
C.
D.
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 5th September Evening Slot
Two Zener diodes (A and B) having breakdown
voltages of 6 V and 4 V respectively, are
connected as shown in the circuit below. The
output voltage V0 variation with input voltage
linearly increasing with time, is given by :
(Vinput = 0 V at t = 0)
(figures are qualitative)
(Vinput = 0 V at t = 0)
(figures are qualitative)
A.
B.
C.
D.
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 5th September Morning Slot
With increasing biasing voltage of a photodiode,
the photocurrent magnitude :
A.
Increases initially and after attaining
certain value, it decreases
B.
Increases linearly
C.
Increases initially and saturates finally
D.
Remains constant
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 4th September Evening Slot
Identify the operation performed by the circuit given below :
A.
AND
B.
NAND
C.
OR
D.
NOT
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 4th September Morning Slot
Take the breakdown voltage of the
zener diode used in the given circuit as 6V.
For the input voltage shown in figure below,
the time variation of the output voltage is:
(Graphs drawn are schematic and not to scale)
zener diode used in the given circuit as 6V.
For the input voltage shown in figure below,
the time variation of the output voltage is:
(Graphs drawn are schematic and not to scale)
A.
B.
C.
D.
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 3rd September Evening Slot
If a semiconductor photodiode can detect a photon with a maximum wavelength of 400 nm, then
its band gap energy is :
Planck’s constant h = 6.63 $ \times $ 10–34 J.s. Speed of light c = 3 $ \times $ 108 m/s
Planck’s constant h = 6.63 $ \times $ 10–34 J.s. Speed of light c = 3 $ \times $ 108 m/s
A.
1.5 eV
B.
2.0 eV
C.
3.1 eV
D.
1.1 eV
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 3rd September Evening Slot
Which of the following will NOT be observed when a multimeter (operating in resistance measuring
mode) probes connected across a component, are just reversed?
A.
Multimeter shows NO deflection in both cases i.e. before and after reversing the probes if the
chosen component is metal wire.
B.
Multimeter shows a deflection, accompanied by a splash of light out of connected component in one direction and NO deflection on reversing the probes if the chosen component is LED.
C.
Multimeter shows an equal deflection in both cases i.e. before and after reversing the probes if
the chosen component is resistor.
D.
Multimeter shows NO deflection in both cases i.e. before and after reversing the probes if the
chosen component is capacitor.
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 3rd September Morning Slot
When a diode is forward biased, it has a
voltage drop of 0.5 V. The safe limit of current
through the diode is 10 mA. If a battery of emf
1.5 V is used in the circuit, the value of
minimum resistance to be connected in series
with the diode so that the current does not
exceed the safe limit is
A.
50 $\Omega $
B.
200 $\Omega $
C.
300 $\Omega $
D.
100 $\Omega $
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 2nd September Evening Slot
In the following digital circuit, what will be the
output at ‘Z’, when the
input (A, B) are (1, 0), (0, 0), (1, 1,), (0, 1)
input (A, B) are (1, 0), (0, 0), (1, 1,), (0, 1)
A.
1, 1, 0, 1
B.
0, 1, 0, 0
C.
1, 0, 1, 1
D.
0, 0, 1, 0
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 9th January Evening Slot
The current i in the network is :
A.
0.6 A
B.
0.3 A
C.
0 A
D.
0.2 A
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 9th January Evening Slot
Two identical capacitors A and B, charged to
the same potential 5V are connected in two
different circuits as shown below at time t = 0.
If the charge on capacitors A and B at time
t = CR is QA and QB respectively, then (Here
e is the base of natural logarithm)
A.
QA = ${{CV} \over e}$, QB = ${{VC} \over 2}$
B.
QA = ${{CV} \over 2}$, QB = ${{VC} \over e}$
C.
QA = VC, QB = ${{VC} \over e}$
D.
QA = VC, QB = CV
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 8th January Evening Slot
In the given circuit, value of Y is :
A.
toggles between 0 and 1
B.
1
C.
will not execute
D.
0
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 8th January Morning Slot
Boolean relation at the output stage-Y for the
following circuit is :
A.
A.B
B.
$\overline A + \overline B $
C.
$\overline A .\overline B $
D.
A + B
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 7th January Evening Slot
In the figure, potential difference between A and B is :
A.
10 V
B.
5 V
C.
zero
D.
15 V
2020
JEE Mains
MCQ
JEE Main 2020 (Online) 7th January Morning Slot
Which of the following gives a reversible operation?
A.
B.
C.
D.
2020
JEE Mains
Numerical
JEE Main 2020 (Online) 6th September Evening Slot
The output characteristics of a transistor is shown in the figure.
When VCE is 10V and IC = 4.0 mA, then value of $\beta $ac is __________.
When VCE is 10V and IC = 4.0 mA, then value of $\beta $ac is __________.
Correct Answer: 150
Explanation:
We know, $\beta $ac = ${{\Delta {I_C}} \over {\Delta {I_B}}}$
$\Delta $IB = (30 - 20) = 10 $\mu $A
$\Delta $IC = (4.5 - 3) = 1.5 mA
$ \therefore $ $\beta $ac = ${{1.5 \times {{10}^{ - 3}}} \over {10 \times {{10}^{ - 6}}}}$ = 150
$\Delta $IB = (30 - 20) = 10 $\mu $A
$\Delta $IC = (4.5 - 3) = 1.5 mA
$ \therefore $ $\beta $ac = ${{1.5 \times {{10}^{ - 3}}} \over {10 \times {{10}^{ - 6}}}}$ = 150
2020
JEE Mains
Numerical
JEE Main 2020 (Online) 9th January Evening Slot
The circuit shown below is working as a 8 V
dc regulated voltage source. When 12 V is used
as input, the power dissipated (in mW) in each
diode is; (considering both zener diodes are
identical) _________.
Correct Answer: 40
Explanation:
Current in circuit = ${{12 - 8} \over {200 + 200}}$ = 10-2 A
So power dissipited in each diode = VI
= 4 $ \times $ 10-2
= 40 mW
So power dissipited in each diode = VI
= 4 $ \times $ 10-2
= 40 mW
2020
JEE Mains
Numerical
JEE Main 2020 (Online) 9th January Morning Slot
Both the diodes used in the circuit shown are
assumed to be ideal and have negligible
resistance when these are forward biased. Built
in potential in each diode is 0.7 V. For the input
voltages shown in the figure, the voltage
(in Volts) at point A is __________.
Correct Answer: 12
Explanation:
VA = 12.7 – 0.7 = 12 Volt
Diode left hand diode is forward biased and right hand diode is reverse biased.
Diode left hand diode is forward biased and right hand diode is reverse biased.
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th April Evening Slot
Figure shows a DC voltage regulator circuit, with a Zener diode of breakdown voltage = 6V. If the
unregulated input voltage varies between 10 V to 16 V, then what is maximum Zener current?
A.
3.5 mA
B.
1.5 mA
C.
2.5 mA
D.
7.5 mA
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th April Morning Slot
The transfer characteristic curve of a transistor, having input and output resistance 100 $\Omega $ and 100 k$\Omega $
respectively is shown in the figure. The voltage and power gain, are respectively:
A.
5 × 104, 5 × 105
B.
5 × 104, 5 × 106
C.
5 × 104, 2.5 × 106
D.
2.5 × 104, 2.5 × 106
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th April Morning Slot
The truth table for the circuit given in the fig. is:
A.
$\left| {\matrix{
A & B & Y \cr
0 & 0 & 1 \cr
0 & 1 & 1 \cr
1 & 0 & 1 \cr
1 & 1 & 1 \cr
} } \right|$
B.
$\left| {\matrix{
A & B & Y \cr
0 & 0 & 1 \cr
0 & 1 & 0 \cr
1 & 0 & 0 \cr
1 & 1 & 0 \cr
} } \right|$
C.
$\left| {\matrix{
A & B & Y \cr
0 & 0 & 1 \cr
0 & 1 & 1 \cr
1 & 0 & 0 \cr
1 & 1 & 0 \cr
} } \right|$
D.
$\left| {\matrix{
A & B & Y \cr
0 & 0 & 0 \cr
0 & 1 & 0 \cr
1 & 0 & 1 \cr
1 & 1 & 1 \cr
} } \right|$
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 10th April Evening Slot
The figure represents a voltage regulator circuit using a Zener diode. The breakdown voltage of the Zener
diode is 6 V and the load resistance is, RL = 4k$\Omega $. The series resistance of the circuit is Ri
= 1 k$\Omega $. If the
battery voltage VB varies from 8 V to 16 V, what are the minimum and maximum values of the current
through Zener diode?
A.
0.5 mA; 8.5 mA
B.
1.5 mA; 8.5 mA
C.
1 mA; 8.5 mA
D.
0.5 mA; 6 mA
Vbreakdwon = 6V, RL = 4k$\Omega $, Ri = 1 k$\Omega $
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 10th April Morning Slot
An n-p-n transistor operates as a common emitter
amplifier, with a power gain of 60 dB. The input
circuit resistance is 100$\Omega $ and the output load
resistance is 10 k$\Omega $. The common emitter
current gain $\beta $ is :
A.
104
B.
102
C.
6 × 102
D.
60
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 9th April Evening Slot
The logic gate equivalent to the given logic
circuit is :-
A.
NAND
B.
AND
C.
NOR
D.
OR
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 9th April Morning Slot
An NPN transistor is used in common emitter
configuration as an amplifier with 1 k$\Omega $ load
resistance. Signal voltage of 10 mV is applied
across the base-emitter. This produces a 3 mA
change in the collector current and 15μA
change in the base current of the amplifier. The
input resistance and voltage gain are :
A.
0.67 kW, 200
B.
0.33 kW, 1.5
C.
0.67 kW, 300
D.
0.33 kW, 300
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 8th April Evening Slot
A common emitter amplifier circuit, built using
an npn transistor, is shown in the figure. Its dc
current gain is 250, RC = 1k$\Omega$ and VCC = 10 V.
What is the minimum base current for VCE to
reach saturation ?
A.
100 $\mu $A
B.
7 $\mu $A
C.
10 $\mu $A
D.
40 $\mu $A
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 8th April Morning Slot
The reverse breakdown voltage of a Zener
diode is 5.6 V in the given circuit.
The current IZ through the Zener is :
The current IZ through the Zener is :
A.
7 mA
B.
17 mA
C.
15mA
D.
10 mA
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th January Evening Slot
In the figure, given that VBB supply can vary from 0 to 5.0 V, VCC = 5V, $\beta $dc = 200, RB = 100 k$\Omega $, RC = 1 k$\Omega $ and VBE = 1.0 V. The minimum base current and the input voltage at which the transistor will go to saturation, will be respectively :
A.
20 $\mu $A and 2.8 V
B.
25 $\mu $A and 2.8 V
C.
20 $\mu $A and 3.5 V
D.
25 $\mu $A and 3.5 V
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 12th January Morning Slot
The output of the given logic circuit is :
A.
$\overline A B$
B.
$AB + \overline {AB} $
C.
$A\overline B + \overline A B$
D.
$A\overline B $
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 11th January Evening Slot
The circuit shown below contains two ideal diodes, each with a forward resistance of 50 $\Omega $. If the battery voltage is 6 V, the current through the 100 $\Omega $ resistance (in Amperes) is :
A.
0.027
B.
0.030
C.
0.036
D.
0.020
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 11th January Morning Slot
In the given circuit the current through Zener Diode is close to:
A.
0.0 mA
B.
6.7 mA
C.
4.0 mA
D.
6.0 mA
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 10th January Evening Slot
For the circuit shown below, the current through the Zener diode is -
A.
5 mA
B.
zero
C.
14 mA
D.
9 mA
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 10th January Morning Slot
To get output 1 at R, for the given logic gate circuit the input values must be
A.
x = 0, y = 0
B.
x = 1, y = 0
C.
x = 0, y = 1
D.
x = 1, y = 1
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 9th January Evening Slot
Ge and Si diodes start conducting at 0.3 V and 0.7 V respectively. In the following figure if Ge diode connection are reversed, the value of V0 changes by : (assume that the Ge diode has large breakdown voltage)
A.
0.8 V
B.
0.6 V
C.
0.2 V
D.
0.4 V
2019
JEE Mains
MCQ
JEE Main 2019 (Online) 9th January Morning Slot
Mobility of electrons in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If, for an n-type semiconductor, the density of electrons is 1019 m$-$3 and their mobility is 1.6 m2/(V.s) then the resistivity of the semiconductor (since it is an n-type semiconductor contribution of holes is ignored) is close to :
A.
$2\,\Omega $m
B.
4$\,\Omega $m
C.
0.4 $\,\Omega $m
D.
0.2 $\,\Omega $m
2018
JEE Mains
MCQ
JEE Main 2018 (Online) 16th April Morning Slot
In the given circuit, the current through zener diode is :
A.
5.5 mA
B.
6.7 mA
C.
2.5 mA
D.
3.3 mA
2018
JEE Mains
MCQ
JEE Main 2018 (Offline)
The reading of the ammeter for a silicon diode in the given circuit
is :
A.
13.5 mA
B.
0
C.
15 mA
D.
11.5 mA
2018
JEE Mains
MCQ
JEE Main 2018 (Online) 15th April Evening Slot
Truth table for the following digital circuit will be :
A.
B.
C.
D.
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