Basic Electronic and Circuits MCQ (Multiple Choice QUESTIONS)
1. A logic circuit that can add two 1-bit numbers and produce outputs for sum and carry
a) full adder
b) semi adder
c) half adder
d) double adder
2. An ordinary transistor is
a) dipolar
b) tripolar
c) bipolar
d) tetra-polar
3. What does a hybrid word mean?
a) unique
b) single
c) dual
d) none of these
4. When the current in the primary coil of a transformer is changed, it induces a change in the magnetic field of
a) capacitor
b) transistor
c) resistor
d) secondary coil
5. We use a wave rectifier for
a) to run A.C. care
b) to run car radios
c) to run batteries
d) to run tape recorders
6. Zener diode is …
a) current stabilizer
b) voltage stabilizer
c) resistance stabilizer
d) none of these
7. We can construct exclusive -OR gates using which other gates?
a) AND, NOT, and OR gate only
b) AND and NAND gate only
c) OR gate only
d) all of these
8. Unit of resistance is …
a) ampere
b) ohm
c) emf
d) none of these
9. The transistor amplifier equation is VCE=VCB+……..
a) 5VBE
b) 3VEB
c) V.B.E.
d) none of these
10. In a reverse-biased junction, its barrier potential will be
a) decreased
b) remain the same
c) increased
d) continuously change
11. Mutual induction depends on
a) resistance changes
b) current changes
c) voltage changes
d) none of the above
12. A transformer that converts unbalanced signals to balanced signals is named…
a) autotransformer
b) balun
c) step-up transformer
d) step down -transformer
13. When we use a single transistor, we obtain which gate?
a) NOR gate
b) OR gate
c) NOT gate
d) NAND gate
14. The circuit that implements OR operation is called…
a) AND gate
b) NOT gate
c) NOR gate
d) OR gate
15. When we increase the number of turns of wire on the secondary coil of a transformer, then …
a) no effect
b) a decrease in the secondary current
c) increase in the secondary current
d) increase in the primary current
16. The deviation in the resistance of a resistor is known as
a) tolerance
b) capacitance
c) inductance
d) none of the above
17. In C.R.O., we connect the grid to which potential?
a) negative potential
b) positive potential
c) both
d) none of these
18. A bipolar transistor is ….
a) free electrons and holes are current carriers
b) free electrons are current carriers
c) holes are current carriers
d) all of these
19. Which one is correct about the potential barrier?
a) amount of energy required to produce half conduction across P.N. junction in reverse bias
b) amount of energy required to produce full conduction across P.N. junction in reverse bias
c) amount of energy required to produce full conduction across P.N. junction in forward bias
d) none of these
20. An electronic component used to store electric charge is …
a) inductor
b) resistor
c) capacitor
d) none of these
21. When will a transistor behave as a linear device …
a) significant signal input
b) small signals input
c) medium signals input
d) all of these
22. What is the function of a linear series voltage converter?
a) resistance voltage converter
b) shunt voltage converter
c) overflow voltage converter
d) all of these
23. Rectifier is a device used to …
a) convert D.C. to A.C.
b) convert A.C. to D.C.
c) both
d) none of the above
24. O.P. -Amp is the abbreviation of
a) opposite amplifier
b) ohm amplifier
c) operational amplifier
d) all of these
25. Which of the following is not an electronic device?
a) A mobile
b) A computer
c) A magnifying glass
d) A keyboard
26. Which of the following is not a physical component of an electronic circuit?
a) Capacitor
b) Inductor
c) Diode
d) Temperature
27. Which of the following is not a property of semiconductors used in electronic devices?
a) They excite electrons
b) They don’t emit light
c) They have high thermal conductivity
d) They have variable electrical conductivity
28. Which of the following is the correct relationship between temperature (T) and mobility (u) of electrons in electronic circuits?
a) u ∝ T-3/2
b) you ∝ T-1/2
c) u ∝ T
d) you ∝ T-1
29. How does temperature affect the recombination rate of electrons in electronic circuits?
a) Recombination rate increases with an increase in the temperature
b) Recombination rate decreases with increase in the temperature
c) Recombination rate is independent of temperature
c) Recombination of electrons doesn’t occur in semiconductors
30. Which of the following is correct about semiconductors in electronic devices?
a) Elemental semiconductors have a direct band gap
b) Compound semiconductors have an indirect band gap
c) Extrinsic semiconductors are injected with impurities
d) Doping is done in Intrinsic semiconductors
31. Which technique can’t be used for generating electron-hole pairs in electronic devices?
a) Thermal excitation
b) Impact ionization
c) Photoexcitation
d) Impurity injection
32. Which of the following is incorrect about semiconductors in electronic devices?
a) Electrons are present below the Fermi level in a semiconductor
b) Degenerated semiconductors behave like a conductor
c) Fermi level is independent of temperature and doping
d) Pentavalent atoms are used in an n-type extrinsic semiconductor
33. Which of the following equations represents mass action law for semiconductors in electronic circuits?
a) n × p = ni2
b) n × p = ni
c) n × p = ni3
d) n × p = ni1/2
34. Which of the following about the Hall Effect in electronic circuits is correct?
a) Hall voltage is very weak in metals as compared to semiconductors
b) Hall voltage is directly proportional to the charge density
c) Hall voltage is inversely proportional to the intensity of the magnetic field
d) Intrinsic semiconductor has a positive temperature coefficient of Hall constant
35. Which of the following is incorrect about a step-graded electronic device junction?
a) Diodes with step-graded junctions are slower than a standard diode
b) They are designed with abrupt junction
c) They are either p+– n or p – n+ junction
d) The depletion layer penetrates more into the lightly doped region
36. Which of the following is correct about photodiode electronic devices?
a) P-N junction is connected in reverse bias.
b) Electron-hole pairs are generated by impurity injection in the depletion layer
c) It is a photovoltaic cell
d) No external voltage is applied
37. Which of the following is wrong about solar cell electronic devices?
a) Solar cell responsivity is directly proportional to the wavelength of light
b) It produces a dark current
c) It is a photovoltaic cell
d) No external voltage is applied
38. What type of semiconductor is used in L.E.D. electronic circuits?
a) Intrinsic semiconductor
b) Compound semiconductor
c) Degenerated semiconductor
d) Compensated semiconductor
39. Which of the following semiconductors is mainly used to construct electronic circuits?
a) Silicon
b) Germanium
c) Selenium
d) Tin
40. Which of the following is correct about NMOS electronic circuits?
a) It has N-substrate
b) For inversion, a positive voltage is applied to the gate terminal
c) For accumulation, a positive voltage is applied to the gate terminal
d) NMOS has holes, as the majority of carriers
41. Which threshold voltage (V.T.) in a MOSFET electronic circuit is wrong?
a) If VT is less, the channel forms quickly for conductivity
b) V.T. can be reduced by reducing oxide layer thickness
c) V.T. is independent of ion implementation
d) V.T. can be reduced by reducing substrate doping
42. Which of the following is the correct relationship between trans-conductance (Gm) and drain to source current (I.D.S.) in an NMOS electronic circuit?
a) Gm ∝ IDS-3/2
b) Gm ∝ IDS-1/2
c) Gm ∝ I.D.S.
d) Gm ∝ IDS1/2
43. In which regions does BJT act as the amplifier electronic device?
a) Cut-off
b) Saturation
c) Active
d) Reverse saturation
44. Which type of semiconductor is used in Tunnel Diode?
a) Compound semiconductor
b) Elemental semiconductor
c) Degenerated semiconductor
d) Extrinsic semiconductor
45. Which of the following is false about the Fermi-Dirac distribution function f(E) used to understand semiconductors in electronic circuits?
a) f(E) is the probability of finding an electron in an energy level E
b) When the temperature decreases, f(E) also increases
c) f(E) doesn’t give the number of electrons in a given energy level
d) f(E) doesn’t give the number of energy levels with electrons
46. An electronic circuit wire of conductivity 5.8 × 107 mho-m is subjected to an electric field of 40 mV/m. What will be its current density?
a) 2.32 × 106 A/m2
b) 1.16 × 106 A/m2
c) 4.64 × 106 A/m2
d) 4.30 × 106 A/m2
47. Mass action law is invalid for which type of semiconductors in electronic devices?
a) Compound
b) Elemental
c) Degenerative
d) Compensated
48. Which is the correct, current expression in an intrinsic semiconductor electronic circuit?
a) ITotal = Ie + Ih
b) ITotal = Ie – Ih
c) ITotal = Ie + 2Ih
d) ITotal = 2Ie + Ih
49. Which of the following equations is valid When an electronic circuit is in equilibrium?
a) Jdrift + Jdiffusion = 1
b) Jdrift + Jdiffusion = 0
c) Jdrift + Jdiffusion = -1
d) Jdrift + Jdiffusion = 2
50. Which of the following is wrong about P-N junction diodes used in electronic devices?
a) They have three modes of operations
b) They have dynamic resistance at low-frequency A.C. voltage
c) They have diffusion capacitance at high-frequency A.C. voltage
d) They can act as ON-OFF switches
51. What is the conductivity of an extrinsic-type semiconductor electronic device at 0K?
a) maximum
b) zero
c) can’t be determined
d) minimum
52. What is the conductivity of an extrinsic-type semiconductor electronic device at 300K?
a) Maximum
b) Zero
c) Can’t be determined
d) Minimum
53. Which of the following effects is responsible for violating the mass action law in degenerative-type semiconductor electronic devices?
a) Thermal effect
b) Bandgap narrowing effect
c) Lattice vibration effect
d) Electronic drift effect
54. Which diodes are used in ultra-high-speed switching electronic circuits?
a) Zener diode
b) Varactor diode
c) Tunnel diode
d) Schottky diode
54. Which diode is used in adjustable bandpass filter electronic circuits?
a) Zener diode
b) Varactor diode
c) Tunnel diode
d) Schottky diode
55. The Forbidden Energy gap (E.G.) of a semiconductor in electronic devices depends on which of the following factors?
a) Interatomic distance
b) Material constant
c) Electron affinity
d) Recombination and Generation
56. Which of the following is the correct order of turn-off times?
a) MOSFET < BJT < IGBT < SCR
b) MOSFET < IGBT < BJT < SCR
c) SCR < BJT < IGBT < MOSFET
d) BJT < MOSFET < IGBT < SCR
57. Which of the following is the correct relation for saturation region in an NMOS electronic circuit?
a) VDS >= VG + VT
b) V.D.S. >= V.G. – V.T.
c) V.D.S. <= V.G. – VT
d) VDS >= VG ± VT
58. Which type of transistors is preferred in digital and analog electronic circuits?
a) BJT
b) JFET
c) MOSFET
d) F.E.T.
59. Which of the following is true about the depletion layer channel in an NMOS electronic circuit?
a) Inverted change in the channel increases from source to drain
b) Inverted charge remains constant
c) Inverted change in the channel decreases from source to drain
d) Potential in the channel decreases from source to drain
60. Semiconductors have which of the following bonds?
a) Co-ordinate bond
b) Covalent bond
c) Electrovalent bond
d) All