JEE Questions for Physics Semiconductor Devices Quiz 19 - MCQExams.com

For a transistor, in a common emitter arrangement, the alternating current gain β is given by

  • Physics-Semiconductor Devices-88280.png
  • 2)
    Physics-Semiconductor Devices-88281.png

  • Physics-Semiconductor Devices-88282.png

  • Physics-Semiconductor Devices-88283.png
A n–p–n transistor having A.0 current gain of 50 is to be used to make an amplifier of power gain of 300. What will be the voltage gain of the amplifier?
  • 8.5
  • 6
  • 4
  • 3
In the CB mode of a transistor, when the collector voltage is changed by 0.5 volt. The collector current changes by 0.05 mA. The output resistance will be
  • 10 k Ω
  • 20 kΩ
  • 5 kΩ
  • 2.5 kΩ
While a collector to emitter voltage is constant in a transistor, the collector current changes by 8.2 mA when the emitter current changes by 8.3 mA. The value offorward current ratio hfe is
  • 82
  • 83
  • 8.2
  • 8.3
Consider an NPN transistor amplifier in common-emitter configuration. The current gain of the transistor is 100. If the collector current changes by 1 mA, what will be the change in emitter current
  • 1.1 mA
  • 1.01 mA
  • 0.01 mA
  • 10 mA
In NPN transistor the collector current is 10 mA. If 90% of electrons emitted reach the collector, then
  • Emitter current will be 9 mA
  • Emitter current will be 11.1 mA
  • Base current will be 0.1 mA
  • Base current will be 0.01 mA
In the study of transistor as an amplifier, if α = Ic /Ieand β = Ic/ Ib, where Ic, Iband Ie are the collector, baseand emitter currents, then

  • Physics-Semiconductor Devices-88288.png
  • 2)
    Physics-Semiconductor Devices-88289.png

  • Physics-Semiconductor Devices-88290.png

  • Physics-Semiconductor Devices-88291.png
An amplifier has a voltage gain Av = 100. The voltage gain in dB is
  • 30 dB
  • 60 dB
  • 3 dB
  • 20 dB
The minimum potential difference between the base and emitter required to switch a silicon transistor \'ON\'is approximately
  • 1 V
  • 3 V
  • 5 V
  • 4.2 V
Which of the following is not a process involved infabrication of IC
  • Polymerization
  • Diffusion
  • Photolithography
  • Metallization
In CE mode, the input characteristics of a transistor isthe variation of
  • IB against VBEat constant VCE
  • IC against VCEat constant VBE
  • IB against IC
  • IE against IC
A common emitter amplifier has a voltage gain of 50, an input impedance of 100 Ω and an output impedance of 200 Ω. The power gain of the amplifier is
  • 500
  • 1000
  • 1250
  • 100
The voltage gain of an amplifier with 9% negative feedback is 10. The voltage gain without feedback willbe
  • 1.25
  • 100
  • 90
  • 10
In a common emitter configuration of a transistor, the voltage drop across a 500 Ω resistor in the collector circuit is 0.5 V when the collector supply voltage is0.96, the base current is

  • Physics-Semiconductor Devices-88297.png
  • 2)
    Physics-Semiconductor Devices-88298.png

  • Physics-Semiconductor Devices-88299.png

  • Physics-Semiconductor Devices-88300.png

  • Physics-Semiconductor Devices-88301.png
The input resistance of a common emitter transistor amplifier, if the output resistance is 500 K Ω, the current gain α = 0.98 and power gain is 6.0625 × 106, is
  • 198 Ω
  • 300 Ω
  • 100 Ω
  • 400 Ω
In a NPN transistor, 108 electrons enter the emitter in 10–8 s. If 1% electrons are lost in the base, the fraction of current that enters the collector and current amplification factor are respectively
  • 0.8 and 49
  • 0.9 and 90
  • 0.7 and 50
  • 0.99 and 99
  • 0.88 and 88
In a CE transistor amplifier, the audio signal voltage across the collector resistance of 2 kΩ is 2 V. If the base resistance is 1kΩ and the current amplification of the transistor is 100, the input signal voltage is
  • 0.1 V
  • 1.0 V
  • 1 mV
  • 10 mV
Given below are symbols for some logic gates
The XOR gate and NOR gate respectively are
Physics-Semiconductor Devices-88306.png
  • I and II
  • II and III
  • III and IV
  • I and IV
The following truth table corresponds to the logic gate
Physics-Semiconductor Devices-88307.png
  • NAND
  • OR
  • AND
  • XOR
The combination of \'NAND\' gates shown here under (figure) are equivalent to
Physics-Semiconductor Devices-88309.png
  • An OR gate and an AND gate respectively
  • An AND gate and a NOT gate respectively
  • AN AND gate and an OR gate respectively
  • An OR gate and a NOT gate respectively
The truth table shown in figure is for
Physics-Semiconductor Devices-88311.png
  • XNOR
  • XOR
  • AND
  • OR
A gate has the following truth table
Physics-Semiconductor Devices-88314.png
  • NOR
  • OR
  • NAND
  • AND
Which of the following gates will have an output of 1

  • Physics-Semiconductor Devices-88316.png
  • 2)
    Physics-Semiconductor Devices-88317.png

  • Physics-Semiconductor Devices-88318.png

  • Physics-Semiconductor Devices-88319.png
This symbol represents
Physics-Semiconductor Devices-88326.png
  • NOT gate
  • OR gate
  • AND gate
  • NOR gate
Which logic gate is represented by following diagram?
Physics-Semiconductor Devices-88327.png
  • AND
  • OR
  • NOR
  • XOR

Physics-Semiconductor Devices-88328.png
  • NAND gate
  • NOR gate
  • NOT gate
  • XNOR gate
To get an output 1 from the circuit shown in the figure,the input must be
Physics-Semiconductor Devices-88329.png
  • A = 0, B = 1, C = 0
  • A = 1, B = 0, C = 0
  • A = 1, B = 0, C = 1
  • A = 1, B = 1, C = 0
The following figure shows a logic gate circuit with two inputs A and B and the output Y. The voltage wave forms of A, B and the output Y are as given
The logic gate is
Physics-Semiconductor Devices-88331.png
  • NOR gate
  • OR gate
  • AND gate
  • NAND gate
Which logic gate is represented by the following combination of logic gates?
Physics-Semiconductor Devices-88333.png
  • OR
  • NAND
  • AND
  • NOR
The output of OR gate is 1
  • If both inputs are zero
  • If either or both inputs are 1
  • Only if both input are 1
  • If either input is zero
The symbolic representation of four logic gates are given below
The logic symbols for OR, NOT and NAND gates are respectively
Physics-Semiconductor Devices-88336.png
  • (iii), (iv), (ii)
  • (iv), (i), (iii)
  • (iv), (ii), (i)
  • (i), (iii), (iv)
The truth-table given below is for which gate
Physics-Semiconductor Devices-88337.png
  • XOR
  • OR
  • AND
  • NAND
Which of the following logic gate is an universal gate?
  • OR
  • NOT
  • AND
  • NOR
In the following circuit, the output Y for all possible inputs A and B is expressed by the truth table
Physics-Semiconductor Devices-88339.png

  • Physics-Semiconductor Devices-88340.png
  • 2)
    Physics-Semiconductor Devices-88341.png

  • Physics-Semiconductor Devices-88342.png

  • Physics-Semiconductor Devices-88343.png
The circuit is equivalent to
Physics-Semiconductor Devices-88345.png
  • NOR gate
  • OR gate
  • AND gate
  • NAND gate
The output y, when all three inputs are first high andthen low, will respectively be
Physics-Semiconductor Devices-88347.png
  • 1, 0
  • 1, 1
  • 0, 0
  • 0, 1
If the two inputs of a NAND gate are shorted, the gate is equivalent to
  • XOR
  • OR
  • NOR
  • NOT
  • AND
A researcher wants an alarm to sound when the temperature of air in his controlled research chamber rises above 40° C or falls below 20° C. The alarm can betriggered by the output of a
  • AND gate
  • NAND gate
  • NOT gate
  • OR gate
In the circuit given A, B and C are inputs and Y is the output
The output of Y is
Physics-Semiconductor Devices-88350.png
  • High for all the high inputs
  • High for all the low inputs
  • High when A = 1, B = 1, C =0
  • Low when A = 0, B = 0, C =1
  • Low for all low inputs
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
Physics-Semiconductor Devices-88352.png
  • OR gate
  • NOR gate
  • AND gate
  • NAND gate
Thermionic emission from a heated filament varies with its temperature T as
  • T–1
  • TT
  • T2
  • T3/2
In diode, when there is saturation current, the plate resistance(rp)is
  • Zero
  • Infinite
  • Some finite quantity
  • Data is insufficient
The grid voltage of any triode valve is changed from–1 volt to – 3 volt and the mutual conductance is3 × 10–4 mho. The change in plate circuit current will be
  • 0.8 mA
  • 0.6 mA
  • 0.4 mA
  • 1 mA
The current in a diode is related to the voltage V by the equation
  • I ∝ V1/2
  • I ∝ V3/2
  • I ∝ V2
  • I ∝ V
In an amplifier the load resistance RL is equal to the plate resistance (rp). The voltage amplification is equal to
  • μ
  • 2μ
  • μ /2
  • μ /4
If Rp = 7 KΩ, gm = 2.5 millimho, then on increasing plate voltage by 50 V, how much the grid voltage ischanged so that plate current remains the same
  • – 2.86 V
  • – 4 V
  • + 4 V
  • + 2 V
The current in a triode at anode potential 100 V and grid potential – 1.2 V is 7.5 mA. If grid potential is changed to – 2.2 V, the current becomes 5.5 mA. The value of transconductance (gm) will be
  • 2 mili mho
  • 3 mili mho
  • 4 mili mho
  • 0.2 mili mho
In a triode amplifier, μ = 25, rp= 40 kilo ohm and load resistance RL = 10 kilo ohm. If the input signal voltage is 0.5 volt, then output signal voltage will be
  • 1.25 volt
  • 5 volt
  • 2.5 volt
  • 10 volt
For a given triode μ = 20. The load resistance is 1.5times the anode resistance. The maximum gain will be
  • 16
  • 12
  • 10
  • None of these
The voltage gain of a triode depends upon
  • Filament voltage
  • Plate voltage
  • Plate resistance
  • Plate current
0:0:1


Answered Not Answered Not Visited Correct : 0 Incorrect : 0

Practice Physics Quiz Questions and Answers