Semiconductor Theory Question & Answers May 26, 2021 By WatElectronics This article lists 100+ Semiconductor Theory MCQs for engineering students. All the Semiconductor Theory Questions & Answers given below includes solution and link wherever possible to the relevant topic. The semiconductor materials are mainly used for manufacturing electronic devices like transistors, diodes, and integrated circuits. In terms of conductivity, the materials are classified into three categories conductor, insulator, and semiconductor. A conductor is a substance that holds the capability to transmit the current freely through the conducting substance, these are also known as good conductors. Example gold, water, etc. Where an insulator is a substance that blocks the flow of current through a medium. Example wood, glass, etc and a semiconductor is a substance that partially allows the current to flow and partially blocks the current flow. Silicon, germanium, gallium arsenide are a few examples of semiconductor materials. In a semiconductor, we can get a flow of current due to two types of charge carriers; one is due to the electrons and the second is due to the holes. Using this concept many electronic components and devices are constructed such as diodes, current resources, voltage resources, amplifier circuits, etc. The main advantage of semiconductor theory is that they require very little voltage for operation, are very compact, and are shockproof. But limit in terms of the high noise level in the devices. This theory is implemented while designing various applications such as microprocessors, microcontrollers, ICs, etc. 1). The electrical conductivity of semiconductor lies in ___________ Inductor Conductor Both a and b None of the above None Hint 2). The semiconductor materials have ________ Free electrons Holes Both a and b None of the above None 3). By adding pentavalent impurity atoms to an intrinsic semiconductor material, the number of ________ increased Free electrons Holes Both a and b None of the above None Hint 4). __________ is an example of semiconductor Resistors Capacitors Op-amps All of the above None Hint 5). Based on their conductivity properties the solids are categorized into ________ One Two Three Four None Hint 6). The resistivity of the germanium is __________ 0.46Ωm 1.0 Ωm 2.1 Ωm 3.0 Ωm None Hint 7). The resistivity of the silicon is __________ 0.46Ωm 100Ωm 210Ωm 640Ωm None Hint 8). How many types of semiconductors are there? One Two Three Four None Hint 9). How many types of extrinsic semiconductors are there? One Two Three Four None Hint 10). How many outer shell valence electrons does silicon have? One Two Three Four None Hint 11). The majority charge carriers in a p-type semiconductor is __________ Holes Electrons Both a and b None of the above None Hint 12). Which one is a conductor example? Copper Glass Both a and b None of the above None Hint 13). ________ is an example of acceptor Boron Phosphorous Copper Glass None Hint 14). The drift current density effected by _______ An electric filed Concentration gradient in holes Concentration gradient in free electrons All of the above None Hint 15). For an intrinsic semiconductor material to have more holes, they are doped with ________atoms Trivalent impurity Pentavalent impurity Both a and b None of the above None Hint 16). How many valence electrons do trivalent impurity atoms have in their valence shell? One Two Three Four None Hint 17). The majority charge carriers in N-type semiconductor is __________ Holes Electrons Both a and b None of the above None Hint 18). Which one is an insulator example? Glass Copper Phosphorous None of the above None Hint 19). Which one is a donor example? Boron Copper Phosphorous None of the above None Hint 20). The diffusion current density effected by _____ Concentration gradient in the hole Concentration gradient in free electrons Both a and b None of the above None Hint 21). The semiconductors doped with trivalent atoms are ________ type of semiconductor P-type N-type Both a and b None of the above None Hint 22). The doping process converts intrinsic semiconductor material into extrinsic semiconductor material True False None Hint 23). In P-type semiconductor ________ are the majority charge carriers Electrons Holes Both a and b None of the above None Hint 24). Atoms consists of ________ Neutrons Electrons Protons All of the above None Hint 25). The hydrogen atom doesn’t have a __________ Neutrons Electrons Protons All of the above None Hint Semiconductor Theory Important MCQs 26). The difference in energy between conduction and valance band is called the band gap True False None Hint 27). The band gap between conduction and valance band in an insulator is ______ Low Very low High Moderate None Hint 28). The band gap in a semiconductor is _______ compared to an insulator Big Very big Smaller Very small None Hint 29). In N-type semiconductor ________ are the minority charge carriers Electrons Holes Both a and b None of the above None Hint 30). In _______ there’s no band gap Conductor Insulator Both a and b None of the above None Hint 31). The solids have ______ Rigid shape Fixed volume Fixed shape All of the above None Hint 32). _________ current happens in the valence band Electron current Valance current Electron or valance current None of the above None Hint 33). The liquids have _________ Non-rigid shape Fixed volume No fixed shape All of the above None Hint 34). _________ current happens in conduction band Electron current Valance current Electron or valance current None of the above None Hint 35). The gases are __________ Non-rigid No fixed volume No fixed shape All of the above None Hint 36). ________ are the crystalline solids Silver Gold Diamond All of the above None Hint 37). ________ is an example of amorphous solid Silver Sugar Glass All of the above None Hint 38). ________ is an example for metal conductor Aluminium Copper Gold, silver All of the above None Hint Read more about Conductors 39). An insulators have_______ Very high resistivity Low conductivity High conductivity Both a and b None Hint 40). _________ is an example for insulator Rubber Silver Gold None of the above None Hint 41). Nucleus consists ______ Only protons Only neutrons Both a and b None of the above None Hint 42). __________ is an example of organic semiconductor GaAS Polypyrole Anthracene None of the above None Hint 43). __________ is an example of inorganic semiconductor GaAS Polypyrole Anthracene None of the above None Hint 44). __________ is an example of organic polymer GaAS Polypyrole Anthracene None of the above None Hint 45). The concentration of electrons in P-type semiconductor is ______________ Low High Very high Moderate None Hint 46). In which semiconductor the energy gap is small? Intrinsic Extrinsic Both a and b None of the above None Hint 47). In which semiconductor the conductivity is low? Intrinsic Extrinsic Both a and b None of the above None Hint 48). Intrinsic semiconductor has________at room temperature Few free electrons Few holes Both a and b None of the above None Hint 49). Intrinsic semiconductor has________at absolute temperature No free electrons No holes Both a and b None of the above None Hint 50).How many valence electrons do pentavalent impurities have? One Two Three Five None Hint Semiconductor Theory Important MCQs with Hints 51). The concentration of electrons in N-type semiconductor is _________ Very high High Low Moderate None Hint 52). The concentration of holes in P-type semiconductor is _________ Very high Very Low High Moderate None Hint Read more about P-type Semiconductor 53). How many valence electrons do trivalent impurities have? One Two Three Four None Hint 54). Germanium is an indirect bandgap semiconductor? True False None Hint 55). What is the unit of charge? Voltmeter Ampere Coulombs None of the above None Hint 56). The compound semiconductors are categorized into ________ One Two Three Four None Hint 57). How many energy levels are possible in one atom? Six Eight Three Seven None Hint 58). The energy gap in insulators is _______ >3ev >2ev >4ev >5ev None Hint 59). The concentration of holes in N-type semiconductor is _________ Less High Very high Moderate None Hint Read more about N-type Semiconductor 60). The energy gap in semiconductors is _______ >3ev <3ev >4ev >5ev None Hint 61). In ________ valence band is fully occupied and the conduction band is vacant Insulators Conductors Both a and b None of the above None Hint 62). In ________ both valence band and conduction band overlap each other Insulators Conductors Metals Semiconductors None Hint 63). What is the unit of conductivity? Columbs Volts per meter Siemens/meter None of the above None Hint 64). The aluminium gallium indium phosphide used for wavelengths between ________ 500-900nm 600-800nm 560-650nm None of the above None Hint 65). The bandgap in copper-zinc tin sulfide material is ______ 0.9ev 2ev 5.6ev 1.49ev None Hint 66). The bandgap in copper-zinc antimony sulfide material is ______ 2.2ev 2ev 5.6ev 1.49ev None Hint 67). The gallium arsenide used for ____ Fast electronics Near IR LEDs High-efficiency solar cells All of the above None Hint 68). ________ material is used for ultraviolet LEDs Boron arsenide Boron nitride Gallium phosphide None of the above None Hint 69). The bandgap in boron nitride material is ______ 2.2ev 2ev 6.36ev 1.49ev None Hint 70). __________ conducts electrical current easily Conductor Semiconductor Insulator None of the above None Hint 71). Which of the following has only one valence electron? Conductor Semiconductor Insulator None of the above None Hint 72). Which of the following has eight valence electrons? Conductor Semiconductor Insulator None of the above None Hint 73). The bandgap in boron arsenide material is ______ 2.2ev 1.14ev 6.36ev 1.49ev None Hint 74). The resistance is very high in __________ Conductor Semiconductor Insulator None of the above None Hint 75). The resistance is very small in __________ Conductor Semiconductor Insulator None of the above None Hint Semiconductor Theory Important MCQs for Quiz 76). Which of the following has a positive temperature coefficient? Conductor Semiconductor Insulator None of the above None Hint 77). Which of the following has a negative temperature coefficient? Conductor Semiconductor Insulator Both b and c None Hint 78). The bandgap in gallium phosphide material is ______ 2.26ev 1.14ev 6.36ev 1.49ev None Hint 79). The relative conductivity of conductor is _________ Large Small Medium None Hint 80). The relative resistance of conductor is _________ Large Small Medium None Hint 81). The phosphorous impurity ionization energy in silicon is around________ 2.26ev 0.045ev 6.36ev 1.49ev None Hint 82). The bandgap in gallium arsenide material is around ______ 2.26ev 1.43ev 6.36ev 1.49ev None Hint 83). The arsenic impurity ionization energy in silicon is around________ 2.26ev 0.045ev 0.05ev 1.49ev None Hint 84). The boron impurity ionization energy in germanium is around________ 2.26ev 0.0104ev 0.05ev 1.49ev None Hint 85). The aluminium impurity ionization energy in germanium is around________ 0.0102ev 0.0104ev 0.05ev 1.49ev None Hint 86). The relative conductivity of insulator _________ Small Large Medium None Hint 87). The silicon material is _______ Cheap Ultra-high purity Both a and b None of the above None Hint 88). The band gap in aluminum gallium arsenide is ____________ 0.0102ev 0.0104ev 0.05ev 1.42ev None Hint 89). The relative conductivity and relative resistivity of semiconductor both are ________ Small Large Medium None Hint 90). The boron impurity ionization energy in silicon is around________ 0.0102ev 0.0104ev 0.045ev 1.49ev None Hint 91). The selenium impurity ionization energy in gallium arsenide is around________ 0.0102ev 0.0059ev 0.045ev 1.49ev None Hint 92). The tellurium impurity ionization energy in gallium arsenide is around________ 0.0102ev 0.0058ev 0.045ev 1.49ev None Hint 93). The beryllium impurity ionization energy in gallium arsenide is around________ 0.028ev 0.0058ev 0.045ev 1.49ev None Hint 94). The aluminium ionization energy in silicon is around________ 0.028ev 0.0058ev 0.06ev 1.49ev None Hint 95). The band gap in indium gallium arsenide is ____________ 0.36ev 0.0104ev 0.05ev 1.42ev None Hint 96). The phosphorous impurity ionization energy in germanium is around________ 0.028ev 0.0058ev 0.012ev 1.49ev None Hint 97). The zinc impurity ionization energy in gallium arsenide is around________ 0.028ev 0.0058ev 0.012ev 0.0307ev None Hint 98). The band gap in gallium phosphide material is ____________ 0.36ev 0.0104ev 1.35ev 1.42ev None Hint 99). The cadmium impurity ionization energy in gallium arsenide is around________ 0.028ev 0.0058ev 0.0347ev 0.0307ev None Hint 100). The germanium material has ______ High mobility High purity material Both a and b None of the above None Hint Semiconductor Theory Important MCQs for Exams 101). The arsenic impurity ionization energy in germanium is around________ 0.028ev 0.0127ev 0.0347ev 0.0307ev None Hint 102). The extrinsic semiconductor further classified into ______ One Two Three Four None Hint 103). In which type of semiconductor electric density is greater than hole density? N-type extrinsic semiconductor P-type extrinsic semiconductor Both a and b None of the above None Hint 104). ________ is an example of semiconductor Resistors Capacitors Op-amps All of the above None Hint 105). Which one is a two-terminal semiconductor device? Schottky diode FET IGBT None of the above None Hint 106). Which one is a three-terminal semiconductor device? Thyristor Solar cell LED None of the above None Hint 107). In which type of semiconductor the hole density is greater than the electric density? N-type extrinsic semiconductor P-type extrinsic semiconductor Both a and b None of the above None Hint 108). What are the applications of semiconductor devices? Microprocessors Analog circuits High voltage applications All of the above None Hint 109). The power range of super junction MOSFET is _________ Up to 1KW Up to 5KW Up to 8KW Up to 10KW None Hint 110). The power range of IGBT is _________ Up to 1Kw Up to 5Kw Several Mws Up to 10Kw None Hint 111). The power range of Sic is _________ Up to 1Kw Up to 5Kw Several Mws Several 100’s Kw None Hint 112). The power range of GaN is _________ Up to 1Kw Few Kw Several Mws Several 100’s Kw None Hint 113). The thermal conductivity of silicon is ________ 1w/cmk 10w/cmk 1.5w/cmk 21w/cmk None Hint 114). The band gap of silicon is _________ 1ev 2ev 4ev 1.11ev None Hint 115). The breakdown field of silicon is ________ 0.3MV/cm 0.50MV/cm 0.90MV/cm 0.20MV/cm None Hint 116). The semiconductor material silicon used in _______ Power amplifiers Mixed signal, MM-wave None of the above None Hint 117). The semiconductor material gallium arsenide used in ____________ ULSI, power amplifiers RF, microwave, MM wave Mixed-signal, MM-wave None of the above None Hint 118). The semiconductor material silicon-germanium used in ____________ Power amplifiers RF, microwave Mixed-signal, MM-wave, DSP Both b and c None Hint 119). The semiconductor material GaN used in _____________ Power amplifiers RF, microwave power amplifiers Mixed-signal, MM-wave, DSP Both b and c None Hint 120). What is the standard form of AIP? Aluminum Ionic Phosphide Aluminum Indium Phosphide Aluminum Phosphide None of the above None Hint 121). What is the standard form of AIAS? Aluminum Ionic Phosphide Aluminum Indium Arsenide Aluminum Arsenide None of the above None Hint 122). The thermal conductivity of silicon carbide is ________ 2.0w/cmk 4.9w/cmk 3.0w/cmk 6.0w/cmk None Hint 123). The breakdown field of silicon carbide is around __________ 3.5mv/cm 4.5mv/cm 5.5mv/cm 6.5mv/cm None Hint 124). The band gap of silicon carbide is around __________ 1ev 2ev 3.26ev 4.5ev None Hint 125). _________ are the compound semiconductors Indium phosphide Aluminum phosphide Gallium phosphide All of the above None Hint Semiconductor Theory Important MCQs for Interviews 126). Which one is an elemental conductor? Aluminum arsenide Gallium arsenide Germanium, silicon All of the above None Hint 127). The Bohr model proposed in ________ 1915 2000 2012 2009 None Hint 128). Which one is a minority carrier device? BJT PN diode JFET None of the above None Hint 129). Which one is a majority carrier device? Schottky diode Power MOSFET JFET All of the above None Hint 130). The band gap of gallium nitride is around _______ 1ev 2ev 3.39ev 1.11ev None Hint 131). The breakdown field of gallium nitride is ________ 0.3MV/cm 0.50MV/cm 3.4MV/cm 0.20MV/cm None Hint 132). The thermal conductivity of gallium nitride is ________ 1w/cmk 10w/cmk 1.5w/cmk 2.0w/cmk None Hint 133). The power semiconductor switching devices categorized into _________ One Two Three Four None Hint 134). Which one is a photodetector? Photothyristors TVS diodes Zener diodes None of the above None Hint 135). Which one is a composite optical device? Photo couplers Photo interrupters GaAs IC’s Both a and b None Hint 136). ________ are the hybrid IC’s GaAs MMICs Thin and thick membrane None of the above None Hint 137). Which one is a light-emitting LED? Switching diodes Zener diodes Laser diodes All of the above None Hint 138). Which one is an analog IC? Op-amps BUS switching CMOS logic IC’s All of the above None Hint 139). Which one is a logic IC? CMOS logic IC’s Bus switches General purpose logic IC’s All of the above None Hint 140). The maximum frequency of IGBT is _________ 10KHz 40KHz 60KHz 80KHz None Hint 141). The maximum frequency of MOSFET is _________ 1MHz 40KHz 60KHz 80KHz None Hint 142). ________ elements have five valence electrons P, sb, As, Bi Al, Ga B, In None of the above None Hint 143). __________ type semiconductors are the semiconductors obtained by pentavalent impurity atoms N-type semiconductors P-type semiconductors Both a and b None of the above None Hint 144). __________ type semiconductors are the semiconductors obtained by trivalent impurity atoms N-type semiconductors P-type semiconductors Both a and b None of the above None Hint 145). Which one is an N-type semiconductor? Arsenic Aluminum Gallium Boron None Hint 146). Which one is a P-type semiconductor? Arsenic Boron Phosphorous None of the above None Hint 147). The depletion region depends on ________ Extent of doping Type of biasing Both a and b None of the above None Hint 148). How many doping regions does the transistor have? One Two Three Four None Hint 149). Which one is a type of power diode? Standard recovery diodes Silicon carbide diodes Schottky diodes Fast recovery diodes All of the above None Hint Read more about Diodes 150). The gains in common base amplifier and common emitter amplifier are ______ Current gain Voltage gain Power gain All of the above None Hint Semiconductor Theory Important MCQs for Engineers 151). In which type of semiconductor the conductivity an increases with increase in temperature? Intrinsic Extrinsic Both a and b None of the above None Hint 152). In an extrinsic semiconductor, the conductivity depends on the amount of impurity added? True False None Hint 153). The semiconductor doesn’t obey ohms law? True False None Hint 154). ________ is a most abundant carrier Minority carriers Majority carriers Both a and b None of the above None Hint 155). The silicon provides ____________ High density Excellent energy resolution Excellent position resolution All of the above None Hint 156). How many types of metal-semiconductor functions are there? One Two Three Four None Hint 157). ________ is a least abundant carrier Minority carriers Majority carriers Both a and b None of the above None Hint 158). The MESFET used in _____ Cellular phones Radars High-frequency devices All of the above None Hint 159). The metal-semiconductor field-effect transistor fabricated in _________ Silicon GaAs Both a and b None of the above None Hint 160). Based on geometry the carbon nano-tubes are ________ One Two Three Four None Hint 161). Which diode is also known as hot barrier diode? Schottky diode Photo diode Zener diode None of the above None Hint 162). Which material is used to manufacture light depend on resistor? Cadmium sulphide Cadmium selenide Lead sulphide All of the above None Hint 163). How many types of GaAs devices are there? One Two Three Four None Hint 164). The advantages of tunnel diode are ________ High speed Low noise Low power All of the above None Hint 165). The tunnel diode used in ____________ Microwave oscillator Relaxation oscillator Logic memory storage devices All of the above None Hint 166). __________ diode is also known as Eskai diode Zener Photo Tunnel None of the above None Hint 167). The varactor diode used in ________ AFC circuits TV receivers Used in FM radio All of the above None Hint Read more about Varactor Diode Time's up
