CBSE Questions for Class 12 Medical Physics Semiconductor Electronics: Materials, Devices And Simple Circuits Quiz 12 - MCQExams.com

For a transistor amplifier power gain and voltage gain are $$7.5$$ and $$2.5$$ respectively. The value of the current gain will be:
  • $$0.33$$
  • $$0.66$$
  • $$0.99$$
  • $$3$$
In a $$NPN$$ transistor working as a common base amplifier, current gain is $$0.96$$ and emitter current is $$7.2\ mA$$. The base current is 
  • $$0.4\ mA$$
  • $$0.2\ mA$$
  • $$0.29\ mA$$
  • $$0.35\ mA$$
In a P-N  junction, a potential barrier exists across the function. A hole with kinetic energy of 300 meV *approaches the junction Find the kinetic energy of the hole it crosses the junction it the hole approached  the Junction from the p-side and
  • 105 me V
  • 55 me V
  • 50 me V
  • 100 me V
The magnitude of the force between a pair of conductors, each of length 110 cm, carrying a current of 10 A and separated by a distance of 10 cm is
  • $$55 \times 10 ^ { - 5 } N$$
  • $$44 \times 10 ^ { - 5 } N$$
  • $$33 \times 10 ^ { - 5 } N$$
  • $$22 \times 10 ^ { - 5 } N$$
In the following common emitter circuit if $$\beta = 100, V _ { C E } = 7 V , V _ { B E } = \text { negligible, } R _ { C } = 2 \mathrm { k } \Omega $$ then $$I _ { B }$$ is
1298793_4be923aa52c044499087b19925789f90.png
  • $$0.01 \mathrm { mA }$$
  • $$0.04 \mathrm { mA }$$
  • $$0.02 \mathrm { mA }$$
  • $$0.03 \mathrm { mA }$$
Which of the following is not a rectifier circuit ?
  • none of these
Find the value of $${ V }_{ 0 }$$
1350502_81a6bdedc4e14fbb80921dc80902dbf3.png
  • 5.7 V
  • 5.3 V
  • 6 V
  • 5 V
When PN junction os forward biased , the current in junction 
  • Increase
  • decrease
  • remains same
  • None of these
The maximum efficiency of full wave rectifier is:
  • $$100$$%
  • $$25.20$$%
  • $$42.2$$%
  • $$81.2$$%
A PN-junction has a thickness of the order of :
  • $$1\, gm$$
  • $$1\, mm$$
  • $$1\, \mu m$$
  • $$1\, pm$$
The output of the given logic circuit is:
1332828_70cf8133b2a546eba6057a38485920ac.PNG
  • $$\bar { A} B$$
  • $$A\bar { B} $$
  • $$AB+\bar {AB } $$
  • $$A\bar { B} +\bar { A} B$$
The current gain of a common emitter amplifier is $$69$$. If the emitter current is $$7.0\ mA$$, collector current is
  • $$69\ mA$$
  • $$6.9\ mA$$
  • $$0.69\ mA$$
  • $$9.6\ mA$$

In a p-type semiconductor, the acceptor level lies 
  • near the conduction band
  • half way between conduction and valence bands
  • within conduction band
  • near the valence band
To get output $$'1'$$ and $$R$$, for the given logic gate circuit the input values must be
1330615_9bab795daadd40b2afaf90ba09d6a807.png
  • $$X = 0, Y = 1$$
  • $$X = 1, Y = 1$$
  • $$X = 0, Y = 0$$
  • $$X = 1, Y = 0$$
Which of the following elements is added to turn artificial diamond into semi conductors?
  • Beryllium
  • Boron
  • Magnesium
  • Calcium
The current gain of a transistor in common base mode is 0.If the change in emitter current is 5 mA then the change in collector current is
  • 4..95 mA
  • 5.4 mA
  • 5.99 mA
  • 0.198 mA
A Zener diode 
  • has negative temperature coefficient of resistance.
  • has sharp breakdown at low reverse voltage.
  • rectifies alternating voltage.
  • is operated only in forward bias.
In a semiconductor
  • There are no free electrons at any temperature
  • The number of free electrons is more than that of the conductor.
  • There are no free electrons at $$0K$$
  • None of these
The current gain of a transistor in a common base arrangement is $$0.98$$. Find the changes in collector current corresponding to a change of $$5.0$$ mA in emitter current. What would be the change in base current?
  • $$4.9 mA, 0.1 mA$$
  • $$4.9 mA, 0.2 mA$$
  • $$5.9 mA, 0.3 mA$$
  • $$5.9 mA, 0.8 mA$$
In a semiconductor
  • There are no free electrons at any temperature
  • The number of free electrons is more than in a conductor
  • There is no free electrons at OK
  • None of these
With  rise in temperature the electrical conductivity of intrinsic semiconductor:
  • increases
  • decreases
  • first increases and then decreases
  • first decreases and then increases
Wire $$P$$ and $$Q$$ have the same resistance at a ordinary room  temperature .When heated resistance  at a ordinary room temperature .When heated resistance of $$P$$ increases and that of $$Q$$ decreases. we conclude that
  • $$P$$ is semiconductor and $$Q$$ is conductor
  • $$P$$ is conductor and $$Q$$ is semiconductor
  • $$P$$ is n-type semiconductor and $$Q$$ is $$p-$$ type conductor
  • None of the above
In the circuit, if the forward voltage drop for the diode is  $$0.5{ V },$$  the current will be :
1434057_e06e7668060c456ea3076d46382abe87.png
  • $$3.4{ mA }$$
  • $$2{ mA }$$
  • $$2.5{ mA }$$
  • $$3{ mA }$$
Symbolic representation of photodiode is
The output of the given circuit in the figure.
1504861_cfaf9101937a4de6a478c7bbbb7aa5a3.png
  • would be zero at all times
  • would be like a half-wave rectifier with positive cycles in output
  • would be like a half -wave rectifier with negative cycles in output
  • would be like that of a full wave rectifier
In the forward bias characteristic curve, a diode appears as :
  • an OFF switch
  • a high resistance
  • an ON switch
  • a capacitor
In a $$\mathrm { n }$$ -p-n transistor circuit, the collector current is $$10 \mathrm { mA }$$ . If $$95$$ percent of the electrons emitted reach the collector, which of the following statements are true?
  • The emitter current will be 8$$\mathrm { mA }$$
  • The base current will be $$2 \mathrm { mA }$$
  • The base current will be $$ 0.53\mathrm { mA }$$
  • None of these
Efficiency of half wave rectifier is:
  • 40.6 %
  • 4.06 %
  • 0.406 %
  • 0.0406 %
Two constant parallel forces act on a wheel provided in a transistor for tunning as shown in the figure. If the wheel rotates then the work done per rotation will be
1457272_9b76b6b3670f40eb983fdafecc4fd981.png
  • 0.05 joule
  • 0.0015 joule
  • 0.031 joule
  • 0.062 joule
The $$PN$$ junction diode is used as 
  • An amplifier
  • A rectifier
  • An oscillator
  • A modulator
In the circuit below, the value of current is 
1820586_7f40f452933f4f17a2f4b6e71731c542.png
  • $$0\ amp$$
  • $$10^{-2}\ amp$$
  • $$10^2\ amp$$
  • $$10^{-3}\ amp$$
Identity the gate in the figures
1547720_d1a9aeab81484cb3b45f7d6361a948f2.png
  • AND
  • NOR
  • XOR
  • NAND
Select and write the correct option from the options given in each question:
Optical Detector is:
  • Diode Laser
  • Laser
  • LED
  • Photo Diode
Find current through the ideal diode.
1566205_bff710290d2742229ecbd58ec9ffa976.png
  • Zero
  • 20A
  • 0.05 A
  • 0.15 A
The circuit given is equivalent to
1524999_6136b97821ba411d9d05d6926cefe18d.png
  • OR gate
  • AND gate
  • NAND gate
  • NOR gate
Logic gate for inpute A an  B is given in figure .
Which table is correct for given gates system:
1613210_34cd2d4f63fe48969a31c9d9526e6b3e.png
In a full wave rectifier in which input voltage is represented by $$V=V_M\sin \omega t$$, then peak inversion voltage of non conducting diode will be?
  • $$-V_M$$
  • $$V_M/2$$
  • $$2V_M$$
  • $$0$$
Determine the current through zener diode for the circuit shown in figure is: (Given: zener diode break down voltage $$V_z=5.6V$$)
1611265_c9f30b27474b40969ebbd9793b2a16e0.png
  • $$7mA$$
  • $$17mA$$
  • $$10mA$$
  • $$15mA$$
Thermistor is a semiconductor device whose temperature coefficient of resistance is
  • Large and negative
  • Small and negative
  • Large and positive
  • Small and positive
For the following combination of gates, select the correct statement
1591421_fe1c08d2475944d48f1b95ce01a9717e.PNG
  • The output is $$1$$ when both the inputs are $$1$$
  • The output is $$0$$ when both the inputs are $$0$$
  • The output is $$0$$ when the two inputs differ
  • The outputs is $$1$$ when the two inputs differ
The figure represents a voltage regulator circuit using a Zener diode. The breakdown voltage of the Zener diode is 6V and the load resistance is $$R_L = 4 k \Omega$$. The series resistance of the circuit is $$R_i = 1 k \Omega$$. If the battery voltage $$V_B$$ varies from $$8V$$ to $$16V$$, what are the minimum and maximum values of the current through Zener diode ? 

1614647_eaf001927ab6481e980e46d1b7f39003.png
  • $$0.5 \, mA ; \, 6 \, mA$$
  • $$0.5 \, mA ; \, 8.5 \, mA$$
  • $$1.5 \, mA ; \, 8.5 \, mA$$
  • $$1 \, mA ; \, 8.5 \, mA$$
Figure shown 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 the maximum Zener current ?
1615164_8407f4dc350745ceb96afe4d48cf04ee.png
  • $$2.5 \, mA$$
  • $$3.5 \, mA$$
  • $$7.5 \, mA$$
  • $$1.5 \, mA$$
For transistor, the current ratio $$'\beta_{dc}'$$ is defined as the ratio of?
  • Collector current to emitter current
  • Collector current to base current
  • Base current to collector current
  • Emitter current to collector current
A device or power strip designed to protect electronic equipment from power surges and spikes is known as.....
  • Surge Suppressors
  • Ping
  • Gateway
  • None of these
A thin plate or board that contains electronic components is called.....
  • RAM
  • ROM
  • Circuit Board
  • All the above
The impurity added in germanium crystal to make $$n-$$ type semi-conductor is:
  • aluminium
  • gallium
  • iridium
  • phosphorus
The valence of an impurity added to germanium crystal in order to convert it into a $$P-$$ type semi conductor is
  • $$6$$
  • $$5$$
  • $$4$$
  • $$3$$
The given transistor operates in saturation region then what should be the value of $$V_{BB}: (R_{out}=200\Omega, R_{in}=100 K\Omega, V_{CC}=3$$ volt, $$V_{BE}=0.7$$ volt, $$V_{CE}=0, \beta =200)$$.
1631459_581f23de15864ac5a05359af5f040051.PNG
  • $$4.1$$ volt
  • $$7.5$$ volt
  • $$8.2$$ volt
  • $$6.8$$ volt
Assertion: Gallium arsenide phosphide is used in red $$L.E.D$$
Reason: Its work function lies b/w $$1.65ev$$
  • If both assertion and reason are true and reason is the correct explanation of assertion.
  • If both assertion and reason are true but reason is not correct explanation of assertion.
  • If assertion is true but reason is false.
  • If both assertion and reason are false.
In an insulator, band gap of the order of?
  • $$0.1eV$$
  • $$1eV$$
  • $$5eV$$
  • $$100eV$$
  • $$1MeV$$
0:0:1


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