CBSE Questions for Class 12 Engineering Physics Semiconductor Electronics: Materials,Devices And Simple Circuits Quiz 3 - MCQExams.com

Which one of the following statement is false 
  • Work is a state finction
  • temperature is a state function
  • Change in the state is completely defined when the initial and final states are specified
  • Work appears at the boundary of the system
Boolean Expression for the gate circuit shown in the figure is
16562.png
  • $$A. 1 = A$$
  • $$A.\bar{A}=0$$ 
  • $$A.A = A$$
  • $$A.0 = 0$$
NAND gate in the following is
The logic gate having following truth table is
A   B   Y
0    0   1
0    1    1
1    0    1
1    1    0 
  • XOR
  • OR
  • AND
  • NAND
The symbolic representation of four logic gates are given below :
The logic symbols for OR, NOT and NAND gates are respectively :

71442.jpg
  • (i), (iii), (iv)
  • (iii), (iv), (ii)
  • (iv), (i), (iii)
  • (iv), (ii), (i)
In n-type of semiconductor, majority carries are
  • Positron
  • Electron
  • Holes
  • Impure particles
Number of electrons in the valence shell of a semiconductor is
  • $$1$$
  • $$2$$
  • $$3$$
  • $$4$$
Semiconductors are generally made up of which substance?
  • Silicon
  • Carbon
  • Phosphorus
  • Boron
In an intrinsic semiconductor, the number of electrons in the conduction band is ________ the number of holes in the valence band.
  • equal to
  • less than
  • greater than
  • none of these
Which are good conductors ?
  • silicon
  • Silver
  • copper
  • glass
The energy gap in glass at room temperature is
  • Greater than that in a semiconductor.
  • Less than that in a good conductor.
  • Greater than that in a good conductor.
  • Both (1) and (3) are true.
Materials which allow only larger currents to flow through them are
  • Insulators
  • Semi-conductors
  • Conductors
  • Alloys
In an intrinsic semiconductor, if $$N_e$$ is the number of electrons in the conduction band and $$N_p$$ is the number of holes in the valence band then.
  • $$N_e > N_p$$
  • $$N_e = N_p$$
  • $$N_e < N_p$$
  • None of the above
The forbidden gap for pure silicon at room temperature is .......................... eV.
  • Less than one
  • 1.1
  • 3
  • 9
A pure semiconductor at absolute zero has
  • Absence of electrons in the conduction band.
  • All the electrons occupying the valence band.
  • Large $$E_g$$ value.
  • All of the above.
The distinction between conductors, insulators and semiconductors is largely concerned with
  • their ability to conduct current
  • the type of crystal lattice
  • binding energy of their electrons
  • relative widths of their energy gaps
In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of
  • $$1 MeV$$
  • $$0.1 MeV$$
  • $$1 eV$$
  • $$5 eV$$
The gate for which output is high, if at least one input is low is
  • NAND
  • NOR
  • AND
  • OR
Zener diode is used for
  • amplification
  • rectification
  • stabilisation
  • all of the above
The lead marked with the arrow is the _______.
382770_5cd44ba8cd7047f58e2cc66be82af862.png
  • collector
  • base
  • emitter
  • core
Zener diode works on
  • zero bias
  • reverse bias
  • forward bias
  • infinite bias
In insulator
  • valence band is partially filled with electrons
  • conduction band is partially filled with electrons
  • conduction band is filled with electrons and valence band is empty
  • conduction band is empty and valence band is filled with electrons
The diffusion current in a p-n junction is
  • from the n-side to the p-side
  • from the p-side to the n-side
  • from the n-side to the p-side if the junction is forward-biased and in the opposite direction if it is reverse-biased
  • from the p-side to the n-side if the junction is forward-biased and in the opposite direction if it is reverse-biased
For germanium diode, the junction voltage is about _____.
  • $$0.7V$$
  • $$0.3V$$
  • $$0.6V$$
  • $$3V$$
  • 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 of the following logic gates is an universal gate?
  • OR
  • NOT
  • AND
  • NOR
Which among the following is an example of a semiconductor?
  • cuprous oxide
  • iron
  • copper
  • aluminium
$$A$$$$B$$$$Q$$
$$0$$$$0$$$$0$$
$$0$$$$1$$$$1$$
$$1$$$$0$$$$1$$
$$1$$$$1$$$$1$$
The truth table is given above for which of the following gates is correct
  • NAND gate
  • OR gate
  • AND gate
  • NOT gate
Which represents NAND gate?
Which logic gate produces LOW output when any of the inputs is HIGH?
  • AND
  • OR
  • NAND
  • NOR
Zener diode acts as a/an
  • oscillator
  • regulator
  • rectifier
  • fliter
The vacancy created due to the absence of an electron in the valence band of a semiconductor is called a _________ .
  • electron
  • hole
  • proton
  • position
The number $$0$$ (zero) is required for
  • transistor
  • abacus
  • computer
  • calculator
The truth table given below is for (A and B are the inputs, Y is the output)
A B Y
0 0 1
0 1 1
1 0 1
1 1 0
  • NOR
  • AND
  • XOR
  • NAND
LED is a p-n junction diode which is
  • forward biased.
  • either forward biased or reverse biased.
  • reverse biased.
  • neither forward biased nor reverse biased.
A thin wire of resistance $$\displaystyle 4\Omega $$ is bent to form a circle. The resistance across any diameter is:
  • $$\displaystyle 4\Omega $$
  • $$\displaystyle 2\Omega $$
  • $$\displaystyle 1\Omega $$
  • $$\displaystyle 8\Omega $$
In insulators________. (C.B is conduction band and V.B is valence band)
  • V.B. is partially filled with electrons
  • C.B. is partially filled with electrons
  • C.B. is empty and V.B. is filled with electrons
  • C.B. is filled with electrons and V.B. is empty
LCD stands for:
  • Light Carrying Diode
  • Liquid Crystal Display
  • Long Crystal Display
  • Light Crystal Display
The output of NOT gate when its input is $$0$$:
  • is $$1$$
  • is $$0$$
  • can be $$0$$ or $$1$$
  • is $$0$$ and $$1$$
The energy band gap (distance between the conduction band and valence band) in conductor is.
  • $$0$$
  • $$4\overset{o}{A}$$
  • $$10\overset{o}{A}$$
  • $$100\overset{o}{A}$$
In the depletion region of a pn junction, there is a shortage of
  • Acceptor ions
  • Holes and electrons
  • Donor ions
  • None of these
A pn junction is a/an
  • Bidirectional component
  • Unidirectional Component
  • Linear component
  • None of these
The pn junction can be formed by which of the following methods?
  • Grown junction method
  • Alloying method
  • Diffusion method
  • All of these
Optoelectronic devices work on :
  • light
  • electrical current
  • both A and B
  • none of the above
The battery connections required to forward bias a pn junction are ____________
  • +ve terminal to p and -ve terminal to n
  • -ve terminal to p and +ve terminal to n
  • -ve terminal to p and -ve terminal to n
  • None of these
When semiconductor is doped half with trivalent and half with pentavalent impurities, junction formed is known as
  • pn junction
  • barrier junction
  • potential barrier
  • both a and b
The leakage current across a pn junction is due to _________
  • Minority carriers
  • Majority carriers
  • Junction capacitance
  • None of these
Which of the following is/are optoelectronic devices?
  • photodiodes
  • solar cells
  • light emitting diodes
  • all of the above
A hole is
  • A positively charge electron
  • An electron in valence band
  • An unfilled covalent bond
  • An excess electron in covalent bond
At breakdown voltage, the rate of creation of hole-electron pairs is _____  leading to the _______  in current. 
  • increased, decrease
  • increased, increase
  • decreased, increase
  • decreased, decrease
0:0:1


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