CBSE Questions for Class 12 Engineering Physics Semiconductor Electronics: Materials,Devices And Simple Circuits Quiz 14 - MCQExams.com

A logic gate is an electric  
  • Makes logic decision
  • Allows electrons flow only in one direction
  • Work binary algebra
  • Alternates between $$0$$ and $$1$$ values
The given truth table is of
$$A\quad 0\quad 1$$
$$X\quad 1\quad 0$$
  • $$OR$$ gate
  • $$AND$$ gate
  • $$NOT$$ gate
  • None of these
Symbol 
1820857_93d34c133d724997a0c3bd236cdb8983.png
  • $$NAND$$ gate
  • $$NOR$$ gate
  • $$NOT$$ gate
  • $$XNOR$$ gate
GaAs is
  • Element semiconductor
  • Alloy semiconductor
  • Bad conductor
  • Metallic semiconductor
The correct symbol for zener diode is 

1820919_0ecd54870db64c88b9e96b6e01920b45.png
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Both Assertion and Reason are incorrect
Which is the wrong statement in following sentences? A device in which $$P$$ and $$N-$$ type semiconductors are used is more useful then a vacuum type because 
  • Power is not necessary to heat filament
  • It is more stable
  • Very less heat is produced in it
  • Its efficiency is high due to a high voltage across the junction
The output of a $$NAND$$ gate is $$0$$
  • If both input are $$0$$
  • If one input is $$0$$ and the other input is $$1$$
  • If both input are $$1$$
  • Either if both inputs are $$1$$ or if one of the input is $$1$$ and the other $$0$$
When a potential difference is applied across, the current passing through
  • An insulator at $$0K$$ is zero
  • A semiconductor at $$0K$$ is zero
  • A metal at $$0K$$ is zero
  • A $$P-N$$ diode at $$300K$$ is finite, if it reverse biased
The current through an ideal $$PN-$$ junction shown in the following circuit diagram will be 
1820905_c116f3a528b945b8aa50c4e530219ebf.png
  • $$Zero$$
  • $$1\ mA$$
  • $$10\ mA$$
  • $$30\ mA$$
Zener diode is used as 
  • Half wave rectifier
  • Full wave rectifier
  • $$ac$$ voltage stabilizer
  • $$dc$$ voltage stabilizer
Which gates is represented by this figure
1820887_260a8611c4824b4da6ffe8f211500235.png
  • $$NAND$$ gate
  • $$AND$$ gate
  • $$NOT$$ gate
  • $$OR$$ gate
The introduced of a grid in a triode value affects plate current by
  • Making the thermionic emission easier at law temperature
  • Releasing more electrons from the plate
  • By increasing plate voltage
  • By neutralising space charge

1820878_9971713d99da4d9babebe5bfd9efb1c6.png
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Both Assertion and Reason are incorrect
Which is the correct relation for forbidden energy gap in conductor, semi conductor and insulator
  • $$\Delta Eg_{C} > \Delta Eg_{SC} > \Delta Eg_{insulator}$$
  • $$\Delta Eg_{insulator} > \Delta Eg_{SC} > Eg_{conductor}$$
  • $$\Delta Eg_{conductor} > \Delta Eg_{insulator} > \Delta Eg_{SC}$$
  • $$\Delta Eg_{SC} > \Delta Eg_{conductor} > \Delta Eg_{insulator}$$
For non conductor, the energy gap is
  • $$6\ eV$$
  • $$1.1\ eV$$
  • $$0.8\ eV$$
  • $$0.3\ eV$$
At room temperature, a $$P-$$ type semiconductor has
  • Large number of holes and few electrons
  • Large number of free electrons and few holes
  • Equal number of free electrons and holes
  • No electrons or holes

1820931_250bcd0164414199aac929be6ce38a47.png
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Both Assertion and Reason are incorrect
The grid in a triode value is used
  • To increases the thermionic emission
  • To control the plate to cathode current
  • To reduce the inter-electrode capacity
  • To keep cathode at constant potential
There energy band gap is maximum in
  • Metals
  • Superconductors
  • Insulators
  • Semiconductor
The following configuration of gate is equivalent to
1821124_110248e5777a43a0864386294f2bc104.png
  • $$NAND$$
  • $$XOR$$
  • $$OR$$
  • $$None\ of\ these$$
Doid is used as a/an
  • Oscillator
  • Amplifier
  • Rectifier
  • Modulator
The valence band and conduction band of a solid overlap at low temperature, the solid may be
  • A metal
  • A semiconductor
  • An insulator
  • None of these
The charge on a hole is equal to the charge of
  • Zero
  • Proton
  • Neutron
  • Electron
Series resistance is connected in the Zener diode circuit to
  • properly reverse bias the Zener
  • protect the Zener
  • properly forward bias the Zener
  • protect the load resistance
The logic gate obtained by two NAND gate is:
  • AND gate
  • OR gate
  • XOR gate
  • NOR gate
Electric current is due to drift of electron in
  • Metallic conductor
  • Semi-conductor
  • Both $$(a)$$ and $$(b)$$
  • None of these
The mobility of free electron is greater than that of free holes because
  • The carry negative charge
  • They are light
  • They mutually collides less
  • They require low energy to continue their motion
A logic gate is an electronic circuit which
  • makes logical decisions.
  • allows electron flow only in one direction.
  • works using binary algebra.
  • alternates between $$0$$ and $$1$$ value.
The given figure shows the wave forms for two inputs $$A$$ and $$B$$ and that for the output $$Y$$ of a logic circuit. The logic circuit is 
1821193_97344621bf874527be1dc116ab88d89b.png
  • An $$AND$$ gate
  • An $$OR$$ gate
  • An $$NAND$$ gate
  • An $$NOT$$ gate
The symbol shown in the adjoining figure is
1843941_ea229274311447d7864929d226d13e2e.PNG
  • NOT gate
  • OR gate
  • AND gate
  • NOR gate
In the circuit shown, find the current through the Zener diode.
2005158_08b1b6b911504cbdb1a22b5db3b23730.png
  • $$5\ mA$$
  • $$1\ mA$$
  • $$15\ mA$$
  • $$25\ mA$$
A circuit of logic gates given below, some input signal A, B, C are given with their output signal x, y and z is given in respective option, choose correct options :
75083.png
  • If $$A = 1, B = 1, C = 1$$ then $$x = 0, y = 1, z = 1$$
  • If $$A = 0, B = 0$$ and $$C = 1$$ then $$x = 1, y = 0, z = 1$$
  • If $$A = 0, B = 0$$ and $$C = 1$$ then $$x = 1, y = 0, z = 0$$
  • If OR gate is replaced by NOR gate then net output signal of the circuit becomes $$z = 0$$ for the input $$A = 0, B = 0$$ and $$C = 1$$.
The logic circuit shown below has the input waveforms 'A' and 'B' as shown. Pick out the correct output waveform. 
40546.jpg
The following figure shows a logic gate circuit with two inputs A and B the output Y. The voltage waveforms of A, B and Y are as given-
The logic gate is-








68946.jpg
  • OR gate
  • AND gate
  • NAND gate
  • NOR gate
A truth table is given below. Which of the following has this type of truth table ?
A
0
1
0
1
B
0
0
1
1
Y
1
0
0
0
  • XOR gate
  • NOR gate
  • AND gate
  • OR gate
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

75988.jpg
  • $$0, 0$$
  • $$0, 1$$
  • $$1, 0$$
  • $$1, 1$$
A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of:
  • each of them increases
  • each of them decreases
  • copper increases and germanium decreases
  • copper decreases and germanium increases.
A Zener diode is connected to a battery and a load as shown. The currents $$I$$, $$I_Z$$ and $$I_L$$ are respectively
99259.jpg
  • $$12.5 mA, 5 mA, 7.5 mA$$
  • $$15 mA, 7.5 mA, 7.5 mA$$
  • $$15 mA, 7.5 mA, 5 mA$$
  • $$12.5 mA, 7.5 mA, 5 mA$$
Which logic gate is represented by the following combination of logic gates:
76935.png
  • OR
  • NAND
  • AND
  • NOR
Pure silicon crystal of length $$l (0.1m)$$ and area $$A$$($$10^{-4}m^2$$) has the mobility of electrons ($$\mu_e$$) and holes ($$\mu_h$$) as $$0.135  m^2/Vs$$ and $$0.048  m^2/Vs$$ , respectively. If the voltage applied across it is $$2V$$ and the intrinsic charge concentration is $$n_i = 1.5 \times 10^6 m^{-3}$$, then the total current flowing through the crystal is
  • $$8.78\times 10^{-17}A$$
  • $$6.25\times 10^{-17}A$$
  • $$7.89\times 10^{-17}A$$
  • $$2.456\times 10^{-17}A$$
The real time variation of input signals A and B are as shown below. If the inputs are fed into NAND gate, then select the output signal from the following
211270.jpg
The value of the resistor, $$R_S$$, needed in the DC voltage regulator circuit shown here, equals

309961.png
  • $$\dfrac{(V_i+V_L)}{(n+1)I_L}$$
  • $$\dfrac{(V_i-V_L)}{n I_L}$$
  • $$\dfrac{(V_i+V_L)}{n I_L}$$
  • $$\dfrac{(V_i-V_L)}{(n+1)I_L}$$
For both pure and doped silicon, calculate the probability that a state at the bottom of the silicon conduction band is occupied?
211316_25c5cae587714f579924e793731baa78.png
  • 5.20 $$\times$$ 10$$^{-2}$$
  • 1.40 $$\times$$ 10$$^{-2}$$
  • 10.5 $$\times$$ 10$$^{-2}$$
  • 14 $$\times$$ 10$$^{-2}$$
Calculate the probability that a donor state in the doped material is occupied?
211317_4c6a0b993f22422483a9f90f953ceaeb.png
  • 0.824
  • 0.08
  • 0.008
  • 8.2
The following circut represents
211206_997493f2f44f4a21bcc9cac0c58f842a.png
  • OR gate
  • XOR gate
  • AND gate
  • NAND gate
The following configuration of gate is equivalent to
211219.jpg
  • NAND gate
  • XOR gate
  • OR gate
  • NOR gate
The diagram of a logic circuit is given below. The output $$F$$ of the circuit is represented by
211207.jpg
  • $$W. (X +Y)$$
  • $$W. (X .Y)$$
  • $$W + (X.Y)$$
  • $$W + (X +Y)$$
The equivalent resistance of the network shown across the point A and O is R and the resistance of each branch of the octagon is r. Find the value of $$\displaystyle \frac { 210R }{ 47r } $$
333615_c06a2a950a9e4431a5316102bdf3639e.png
  • 5
  • 3
  • 2
  • 4
Find the minimum load resistance which can be used for the zener diode as shown in figure. Given, $$V_Z=10 V, R_Z=0 \Omega,  R=450 \Omega, I_Z(min)=2 mA $$ and $$I_Z(max)=60 mA$$
507026.png
  • $$0 \Omega$$
  • $$333.3 \Omega$$
  • $$31.95 \Omega$$
  • $$319.5 \Omega$$
0:0:1


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