JEE Questions for Physics Semiconductor Devices Quiz 13 - MCQExams.com

For the given combination of gates, if the logic states of inputs A, B, C are as follows A = B = C =0 and A = B = 1, C = 0 then the logic states of output D are
Physics-Semiconductor Devices-87880.png
  • 0, 0
  • 0, 1
  • 1, 0
  • 1, 1
Boolean algebra is essentially based on
  • Symbol
  • Truth
  • Logic
  • Numbers
The logic behind ‘NOR’ gate is that it gives
  • High output when both the inputs are low
  • Low output when both the inputs are low
  • High output when both the inputs are high
  • None of the above
A logic gate is an electronic circuit which
  • Makes logic decisions
  • Allows electrons flow only in one direction
  • Works binary algebra
  • Alternates between 0 and 1 values
How many NAND gates are used to form an AND gate
  • 1
  • 2
  • 3
  • 4
Which of the following gates will have an output of 1?

  • Physics-Semiconductor Devices-87884.png
  • 2)
    Physics-Semiconductor Devices-87885.png

  • Physics-Semiconductor Devices-87886.png

  • Physics-Semiconductor Devices-87887.png
The given truth table is of
Physics-Semiconductor Devices-87889.png
  • OR gate
  • AND gate
  • NOT gate
  • None of these

Physics-Semiconductor Devices-87891.png
  • 0, 0
  • 0, 1
  • 1, 0
  • 1, 1
If A and B are two inputs in AND gate, then AND gate has an output of 1 when the values of A and B are
  • A = 0, B = 0
  • A = 1,B = 1
  • A = 1, B = 0
  • A = 0, B = 1
The Boolean equation of NOR gate is

  • Physics-Semiconductor Devices-87893.png
  • 2)
    Physics-Semiconductor Devices-87894.png

  • Physics-Semiconductor Devices-87895.png

  • Physics-Semiconductor Devices-87896.png
This symbol represents
Physics-Semiconductor Devices-87897.png
  • NOT gate
  • OR gate
  • AND gate
  • NOR gate
The output of a NAND gate is 0
  • If both inputs are 0
  • If one input is 0 and the other input is 1
  • If both inputs are 1
  • Either if both inputs are 1 or if one of the inputs is 1 and the other 0
A gate in which all the inputs must be low to get a high output is called
  • A NAND gate
  • An inverter
  • A NOR gate
  • An AND gate
Sum of the two binary numbers (100010)2 and (11011)2 is
  • (2
  • (2
  • (2
  • (2
Identify the operation performed by the circuit given below
Physics-Semiconductor Devices-87900.png
  • NOT
  • AND
  • OR
  • NAND
Boolean expression for OR gate is

  • Physics-Semiconductor Devices-87902.png
  • 2)
    Physics-Semiconductor Devices-87903.png

  • Physics-Semiconductor Devices-87904.png

  • Physics-Semiconductor Devices-87905.png
The decimal equivalent of the binary number (11010.101)2 is
  • 9.625
  • 25.265
  • 26.625
  • 26.265
The truth table given below is for (A and B are the inputs, Y is the output)
Physics-Semiconductor Devices-87906.png
  • NOR
  • AND
  • XOR
  • NAND
To write the decimal number 37 in binary, how many binary digits are required?
  • 5
  • 6
  • 7
  • 4
In the following combinations of logic gates, the outputs of A, B and C are respectively
Physics-Semiconductor Devices-87908.png
  • 0, 1, 1
  • 0, 1, 0
  • 1, 1, 0
  • 1, 0, 1
In the circuit below, A and B represent two inputs and C represents the output.
The circuit represents
Physics-Semiconductor Devices-87910.png
  • AND gate
  • NAND gate
  • OR gate
  • NOR gate
Identify the true statement of OR gate
  • Output Y will be 1 when the input A or B or both are 1
  • Output Y will be 0 when either of the inputs A and B is 1
  • Output Y will be 1 only when both the inputs A and B are 1
  • Output Y will be 1 only when either of the inputs A and B is 1
The truth table for the following logic circuit is
Physics-Semiconductor Devices-87913.png

  • Physics-Semiconductor Devices-87914.png
  • 2)
    Physics-Semiconductor Devices-87915.png

  • Physics-Semiconductor Devices-87916.png

  • Physics-Semiconductor Devices-87917.png

  • Physics-Semiconductor Devices-87918.png
The following logic circuit represents
Physics-Semiconductor Devices-87920.png

  • Physics-Semiconductor Devices-87921.png
  • 2)
    Physics-Semiconductor Devices-87922.png

  • Physics-Semiconductor Devices-87923.png

  • Physics-Semiconductor Devices-87924.png
The circuit diagram shows a logic combination with the states of outputs X, Y and Z given for inputs P, Q, R and S all at state 1. When input P and R change to state 0 with inputs Q and S still at 1, the states of outputs X, Y and Z change to
Physics-Semiconductor Devices-87926.png
  • 1, 0, 0
  • 1, 1, 1
  • 0, 1, 0
  • 0, 0, 1
  • 0, 1, 1
Truth table for system of four NAND gates as shown in a figure is
Physics-Semiconductor Devices-87928.png

  • Physics-Semiconductor Devices-87929.png
  • 2)
    Physics-Semiconductor Devices-87930.png

  • Physics-Semiconductor Devices-87931.png

  • Physics-Semiconductor Devices-87932.png
Number of secondary electrons emitted per number of primary electrons depends on
  • Material of target
  • Frequency of primary electrons
  • Intensity
  • None of the above
Due to S.C.R in vacuum tube
  • Ip → Decrease
  • Ip – Increase
  • Vp = Increase
  • g = Increase
The grid voltage of any triode valve is changed from –1 volt to –3 volt and the mutual conductance is 3 × 10–4 mho. The change in plate circuit current will be
  • 0.8 mA
  • 0.6 mA
  • 0.4 mA
  • 1 mA
In an amplifier the load resistance RML is equal to the plate resistance (rp). The voltage amplification is equal to
  • µ
  • 2 µ

  • Physics-Semiconductor Devices-87936.png

  • Physics-Semiconductor Devices-87937.png
If Rp = 7KΩ , gm = 2.5 milli mho, then on increasing plate voltage by 50 V, how much the grid voltage is changed so that plate current remains the same
  • –2.86 V
  • –4 V
  • + 4 V
  • + 2 V
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
The plate resistance of a triode is 2.5 × 104 Ω and mutual conductance is 2 × 10–3 mho. What will be the value of amplification factor
  • 50
  • 75
  • 1.25 × 107
  • 2.25 × 107
In a diode valve the cathode temperature must be (ϕ = work function)
  • High and ϕ should be high
  • High and ϕ should be low
  • Low and ϕ should be high
  • Low and ϕ should be low
The amplification produced by a triode is due to the action of
  • Filament
  • Cathode
  • Grid
  • Plate
In an experiment, the saturation in the plate current in a diode is observed at 240 V. But a student still wants to increase the plate current. It can be done, if
  • The plate voltage is increased further
  • The plate voltage is decreased
  • The filament current is decreased
  • The filament current is increased
In a triode amplifier, the value of maximum gain is equal to
  • Half the amplification factor
  • Amplification factor
  • Twice the amplification factor
  • Infinity
For a given triode µ = 20. The load resistance is 1.5 times the anode resistance. The maximum gain will be
  • 16
  • 12
  • 10
  • None of these
The amplification factor of a triode valve is 15. If the grid voltage is changed by 0.3 volt the change in plate voltage in order to keep the plate current constant (in volt) is
  • 0.02
  • 0.002
  • 4.5
  • 5.0

Physics-Semiconductor Devices-87946.png
  • 100 kilo-ohms static
  • 1000 kilo-ohms static
  • 1000 kilo-ohms dynamic
  • 1000 kilo-ohms dynamic
A triode has a mutual conductance of 2 × 10–3 mho and an amplification factor of 50. The anode is connected through a resistance of 25 × 103 ohms to a 250 volts supply. The voltage gain of this amplifier is
  • 50
  • 25
  • 100
  • 12.5
14 × 1015 electrons reach the anode per second. If the power consumed is 448 milliwatts, then the plate (anode) voltage is
  • 150 V
  • 200 V
  • 14 × 448 V
  • 448/14 V
In the circuit of a triode valve, there is no change in the plate current, when the plate potential is increased from 200 volt to 220 volt and the grid potential is decreased from –0.5 volt to –1.3 volt. The amplification factor of this valve is
  • 15
  • 20
  • 25
  • 35
If the amplification factor of a triode (µ) is 22 and its plate resistance is 6600 ohm, then the mutual conductance of this valve in mho is

  • Physics-Semiconductor Devices-87951.png
  • 25 × 10–2
  • 2.5 × 10–2
  • 0.25 × 10–2
The correct relation for a triode is

  • Physics-Semiconductor Devices-87953.png
  • 2)
    Physics-Semiconductor Devices-87954.png
  • Both (a) and (b)
  • None of these
The triode constant is out of the following
  • Plate resistance
  • Amplification factor
  • Mutual conductance
  • All of these
The unit of mutual conductance of a triode valve is
  • Siemen
  • Ohm
  • Ohm metre
  • Joule coulomb–1
With a change of load resistance of a triode, used as an amplifier, from 50 kilo ohms to 100 kilo ohms, its voltage amplification changes from 25 to 30. Plate resistance of the triode is
  • 25 k Ω
  • 75 k Ω
  • 7.5 k Ω
  • 2.5 k Ω
The plate current in a vacuum diode depends on
  • Cathode temperature only
  • Plate voltage only
  • Both plate voltage and cathode temperature
  • None of the above
The introduction of a grid in a triode valve affects plate current by
  • Making the thermionic emission easier at low temperature
  • Releasing more electrons from the plate
  • Increasing plate voltage
  • Neutralizing space charge
0:0:1


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