84 + Interview Questions in Conduction In Semiconductors in Electronic Devices & Circuits Page 1 InterviewSolution

1.	Which of the following represents the continuity equation?(a) dp/dt=-(p-p0)/τp+Dp(d^2p/dx^2)-µpd(ρϵ)/dx(b) dp/dt=-(p-p0)/τp-Dp(d^2p/dx^2)-µpd(ρϵ)/dx(c) dp/dt=-(p-p0)/τp+Dp(d^2p/dx^2)+µpd(ρϵ)/dx(d) dp/dt=(p-p0)/τp-Dp(d^2p/dx^2)-µpd(ρϵ)/dxI have been asked this question during an interview for a job.My question is from The Continuity Equation in division Conduction in Semiconductors of Electronic Devices & Circuits
Answer» CORRECT answer is (a) dp/dt=-(p-p0)/τp+Dp(d^2p/dx^2)-µpd(ρϵ)/dx The BEST explanation: Option a represents the correct EQUATION of the continuity equation for HOLES.

Discussion

2.	Where will be the position of the Fermi level of the n-type material when ND=NA?(a) Ec(b) Ev(c) Ef(d) EfiI have been asked this question during an online interview.Origin of the question is Fermi Level in a Semiconductor having Impurities topic in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» CORRECT CHOICE is (a) Ec The EXPLANATION is: When ND=NA, kTln(ND/NA )=0 So, Ef=Ec.

Discussion

3.	What is the SI unit of conductivity?(a) Ωm(b) (Ωm)-1(c) Ω(d) mThis question was posed to me by my college professor while I was bunking the class.The question is from Conductivity of a Semiconductor in portion Conduction in Semiconductors of Electronic Devices & Circuits
Answer» RIGHT choice is (b) (Ωm)-1 The best I can EXPLAIN: The FORMULA of the conductivity is the σ=1/ρ. So, the unit of resistivity is Ωm. Now, the unit of conductivity becomes the INVERSE of resistivity.

Discussion

4.	Do the Fermi energy level changes in a semiconductor?(a) True(b) FalseThis question was posed to me in my homework.I'd like to ask this question from Charge Densities in a Semiconductor impurities in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Correct CHOICE is (a) True The best explanation: The Fermi ENERGY level changes as the electron and hole concentrations CHANGE because of the formula which defines the position of the Fermi level depending on the CONCENTRATION of HOLES and electrons.

Discussion

5.	What is the range of the carrier lifetime?(a) Nanoseconds to microseconds(b) Nanoseconds to hundreds of microseconds(c) Nanoseconds to tens of microseconds(d) Nanoseconds to millisecondsThe question was asked by my school teacher while I was bunking the class.This question is from Carrier Life time in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Correct option is (b) NANOSECONDS to hundreds of microseconds For EXPLANATION I would say: Carrier lifetime is DEFINED as the existence of any carrier for τ seconds. Carrier lifetime RANGES from nanoseconds to hundreds of microseconds.

Discussion

6.	Identify the correct condition for a semiconductor to be electrically neutral.(a) Nd+p=Na+n(b) Nd-p=Na+n(c) Nd+p=Na-n(d) Nd-p=Na-nI have been asked this question in an interview for job.My question is from Charge Densities in a Semiconductor impurities topic in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Correct OPTION is (a) Nd+p=Na+n The EXPLANATION: The SUM of the NUMBER of DONORS and the holes is equal to the sum of the number of the acceptors and the electrons.

Discussion

7.	At what temperature the donor states are completely ionized?(a) 0 K(b) ROOM(c) 300K(d) 900KI got this question during a job interview.The query is from Donor and Acceptor impurities in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The correct option is (B) ROOM Explanation: At room TEMPERATURE, the donors have donated their ELECTRONS to the CONDUCTION band.

Discussion

8.	Which of the following expression represents the correct formula for the conductivity in an intrinsic material?(a) ρ=e(μn+μp )ni(b) σ=e(μn+μp )ni(c) σ=1/(e(μn+μp )ni)(d) ρ=1/(e(μn+μp )ni)I got this question in unit test.My doubt is from Conductivity of a Semiconductor in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The correct answer is (b) σ=e(μn+μp )ni For explanation I WOULD SAY: OPTION b is the correct FORMULA.

Discussion

9.	The change in the carrier density is due to(a) Flow of incoming flux(b) Flow of outgoing flux(c) Difference of flow between incoming and outgoing flux(d) Difference of flow between incoming and outgoing flux plus generation and minus recombinationI had been asked this question by my school principal while I was bunking the class.My query is from The Continuity Equation topic in portion Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The correct CHOICE is (d) Difference of flow between INCOMING and outgoing flux PLUS generation and minus RECOMBINATION Explanation: The change in the carrier DENSITY describes the continuity equation which is equal to the difference between the incoming and outgoing flux plus generation and minus recombination.

Discussion

10.	From the above equation, assuming the same values for the for ni, n= p and T. Given that p0=10^5cm^-3. Calculate the quasi-fermi energy level in eV?(a) 0.1985(b) 0.15(c) 0.1792(d) 0.1The question was asked in an interview.The query is from Fermi Level in a Semiconductor having Impurities in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Correct CHOICE is (c) 0.1792 Explanation: Using the same equation, SUBSTITUTING the respective values, EFI – EFp=0.1792 EV.

Discussion

11.	The 1-fF (E) increases in which of the following band for n type semiconductor?(a) Conduction band(b) Donor band(c) Acceptor band(d) Valence bandThe question was asked in an interview for job.I'm obligated to ask this question of Charge Densities in a Semiconductor impurities in portion Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Right option is (d) Valence BAND Explanation: For an n-type semiconductor, the PROBABILITY of FF (E) decreases in the valence band. The probability of finding the electron in the conduction band is more.

Discussion

12.	In which range of temperature, freeze out point begins to occur?(a) Higher range(b) Lower range(c) Middle range(d) NoneThis question was addressed to me in examination.The question is from Conductivity of a Semiconductor in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Correct option is (B) Lower RANGE For EXPLANATION I would say: At lower range of TEMPERATURE, the concentration and conductivity DECREASES with lowering of the temperature.

Discussion

13.	In the Hall Effect, the electric field is in x direction and the velocity is in y direction. What is the direction of the magnetic field?(a) X(b) Y(c) Z(d) XY planeThis question was addressed to me in an interview for internship.I'm obligated to ask this question of The Hall Effect in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The CORRECT choice is (c) Z For EXPLANATION I would say: The HALL EFFECT satisfies the Lorentz’s Force which is E=vxB So, the direction of the VELOCITY, electric field and magnetic field should be perpendicular to each other.

Discussion

14.	Which of the following is used as the recombination agent by semiconductor device manufactures?(a) Silver(b) Gold(c) Platinum(d) AluminiumThe question was posed to me in semester exam.I want to ask this question from Carrier Life time topic in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Correct answer is (b) Gold For explanation I WOULD say: Gold is used as a recombination agent because of its chemical PROPERTIES as it was used in the Bohr’s experiment. Thus the device designer can obtain the desired carrier lifetimes by INTRODUCING gold into silicon under CONTROLLED CONDITIONS.

Discussion

15.	Calculate the recombination rate if the excess carrier concentration is 10^14cm^-3 and the carrier lifetime is 1µseconds.(a) 10^8(b) 10^10(c) 10^20(d) 10^14The question was asked during an interview.The query is from Carrier Life time topic in division Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Right option is (C) 10^20 The EXPLANATION: The recombination RATE, R=δn/τ. So, R=10^14 / 10^-6 R=10^20.

Discussion

16.	Is it true, when the temperature rises, the electrons in the conduction band becomes greater than the donor atoms?(a) True(b) FalseThis question was posed to me in an online quiz.Origin of the question is Fermi Level in a Semiconductor having Impurities in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The correct option is (a) True The BEST I can explain: When the temperature increases, there is an INCREASE in the electron-hole pairs and all the donor ATOMS GET ionized, so now the thermally generated electrons will be greater than the donor atoms.

Discussion

17.	Which of the following expressions represent the correct formula for the density of electrons occupying the donor level?(a) nd=Nd-Nd^+(b) nd=Nd-Nd^–(c) nd=Nd+Nd^+(d) nd=Nd+Nd^–I got this question in an international level competition.My question is from Donor and Acceptor impurities topic in division Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The CORRECT answer is (a) nd=Nd-Nd^+ Easiest EXPLANATION: The density of the electrons is equal to the electrons PRESENT in the substrate MINUS the number of DONORS present.

Discussion

18.	Calculate the number of electrons is the number of holes are 1510^10?(a) 1510^10(b) 1.510^8(c) 1.510^9(d) 1.5*10^10This question was addressed to me in a job interview.My query is from Charge Densities in a Semiconductor impurities topic in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Correct ANSWER is (C) 1.510^9 To explain: np=(1.510^10)^2 n1510^10=1.51.510^1010^10 n=1.5*10^9 ELECTRONS.

Discussion

19.	What is the diffusion length for electrons when Dn=10cm^2/s and τn=40s?(a) 50cm(b) 25cm(c) 20cm(d) 15cmThe question was asked in my homework.Asked question is from The Continuity Equation topic in division Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Right choice is (C) 20cm Easiest explanation: Ln=√(DNτn) =√(1040) =20cm.

Discussion

20.	The number of majority carriers that are available for recombining with excess minority carriers decreases as the excess semiconductor becomes intrinsic. Is it true?(a) True(b) FalseThis question was addressed to me in class test.My query is from Carrier Life time in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Correct choice is (a) True Explanation: With the INCREASE in the NUMBER of the majority CARRIERS, the carriers for the recombination will be decreasing with the excess minority carriers and will FINALLY become intrinsic as the concentrations will be same.

Discussion

21.	What does p/τ represent?(a) holes(b) time(c) holes per second lost(d) p per unit timeThe question was asked in my homework.This interesting question is from The Continuity Equation topic in portion Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Correct answer is (c) holes PER second lost To explain: Option (c) REPRESENTS the holes per second lost by RECOMBINATION per UNIT volume.

Discussion

22.	Which is the correct formula for the Jp?(a) Jp=qDdp/dx(b) Jp=pDdn/dx(c) Jp=-qDdp/dx(d) NoneI have been asked this question in a national level competition.This is a very interesting question from Diffusion in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» CORRECT ANSWER is (C) Jp=-qDdp/dx For explanation: Jp is NEGATIVE for the P type of semiconductors.

Discussion

23.	Ef lies in the middle of the energy level indicates the unequal concentration of the holes and the electrons?(a) True(b) FalseI had been asked this question by my college professor while I was bunking the class.This question is from Fermi Level in a Semiconductor having Impurities in portion Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The CORRECT answer is (b) False Explanation: When the EF is in the MIDDLE of the energy LEVEL, it indicates the equal concentration of the holes and electrons.

Discussion

24.	When the temperature of either n-type or p-type increases, determine the movement of the position of the Fermi energy level?(a) Towards up of energy gap(b) Towards down of energy gap(c) Towards centre of energy gap(d) Towards out of pageThis question was addressed to me at a job interview.Asked question is from Fermi Level in a Semiconductor having Impurities topic in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The CORRECT option is (C) Towards CENTRE of ENERGY gap The explanation: whenever the temperature increases, the FERMI energy level tends to move at the centre of the energy gap.

Discussion

25.	At absolute zero temperature, which level is below the Fermi energy level in the case of acceptors?(a) Donor energy level(b) Valence Band(c) Conduction band(d) Acceptor energy levelThe question was asked in exam.My doubt is from Donor and Acceptor impurities topic in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Correct answer is (b) Valence Band The best explanation: At T=0 K, the TEM exp(-∞)=0 in the expression of So, only valence band LIES below the FERMI ENERGY level of the acceptors.

Discussion

26.	The opposite of ionization takes place at which temperature?(a) 0 K(b) ROOM(c) 300 K(d) 900KI have been asked this question by my school principal while I was bunking the class.Question is from Donor and Acceptor impurities in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» RIGHT OPTION is (a) 0 K Easiest explanation: AT 0 K, all the donors and ACCEPTORS are in their lowest ENERGY LEVELS.

Discussion

27.	What is the electric field when the voltage applied is 5V and the length is 100cm?(a) 0.5V/m(b) 5V/m(c) 50V/m(d) NoneThis question was addressed to me during a job interview.I would like to ask this question from Conductivity of a Semiconductor topic in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» RIGHT OPTION is (C) 50V/m For EXPLANATION: E=V/L=5/100cm=5V/m.

Discussion

28.	Which of the following expressions doesn’t represent the correct formula for Drift current density?(a) J=σE(b) J=qnµE(c) J=µE(d) NoneThe question was asked in an internship interview.This interesting question is from Conductivity of a Semiconductor in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The correct choice is (C) J=µE The best explanation: The following formulae REPRESENT the correct EXPRESSION for DRIFT current DENSITY, J=σE And J=qnµE.

Discussion

29.	Which of the following expressions represents the correct distribution of the electrons in the conduction band? (gc(E)=density of quantum states, fF(E)=Fermi dirac probability(a) n(E)=gc(E)fF(E)(b) n(E)=gc(-E)fF(E)(c) n(E)=gc(E)fF(-E)(d) n(E)= gc(-E)fF(-E)This question was posed to me in final exam.I need to ask this question from Electrons and Holes in Semiconductor topic in division Conduction in Semiconductors of Electronic Devices & Circuits
Answer» RIGHT answer is (a) N(E)=gc(E)*fF(E) To EXPLAIN: The DISTRIBUTION of the electrons in the conduction band is given by the product of the density into Fermi-dirac distribution.

Discussion

30.	Calculate the Hall voltage when B=5A/m, I=2A, w=5cm and n=10^20.(a) 3.125V(b) 0.3125V(c) 0.02V(d) 0.002VI had been asked this question by my school teacher while I was bunking the class.My enquiry is from The Hall Effect topic in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» CORRECT OPTION is (d) 0.002V For explanation I WOULD say: Vh=BI/wρ =5=2/ (510^-210^51.610^-19) =0.002V.

Discussion

31.	What does dn/dx represent?(a) Velocity gradient(b) Volume gradient(c) Density gradient(d) NoneThis question was addressed to me in an interview for internship.This intriguing question originated from Diffusion topic in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The CORRECT OPTION is (c) DENSITY gradient For explanation: dn/dx represent velocity gradient.

Discussion

32.	At T=0 K, the location of Fermi level with respect to the Ec and Ed for the n type material is?(a) Above than conduction band(b) Midway(c) Lower than Ed(d) Greater than EdThis question was posed to me in a job interview.This question is from Donor and Acceptor impurities topic in portion Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Correct choice is (B) Midway The best explanation: At T=0 K, the Fermi LEVEL of n BAND lies between the midway of Ec and Ed as intrinsic Fermi level always lies between the Ec and Ev.

Discussion

33.	The intrinsic Fermi level of a semiconductor depends on which of the following things?(a) Emidgap(b) mp^(c) mn^(d) All of the mentionedThe question was asked by my college director while I was bunking the class.Asked question is from Electrons and Holes in Semiconductor topic in portion Conduction in Semiconductors of Electronic Devices & Circuits
Answer» RIGHT OPTION is (d) All of the mentioned Explanation: From the above FORMULA, Efidepends on all of the OPTIONS GIVEN.

Discussion

34.	What is the conductivity when the Hall Effect coefficient is 5 and mobility is 5cm^2 /s.(a) 100 S/m(b) 10 S/m(c) 0.0001S/m(d) 0.01 S/mI had been asked this question in a job interview.I need to ask this question from The Hall Effect in division Conduction in Semiconductors of Electronic Devices & Circuits
Answer» RIGHT CHOICE is (C) 0.0001S/m To EXPLAIN: µ=σR σ =µ/R =5*10^-4/5 =0.0001 S/m.

Discussion

35.	Calculate the emission rate where En=2.5, Nt=10^10cm^-3 and fF (Et)=0.6 .(a) 1510^10(b) 1.510^10(c) 1510^11(d) 1.510^11I have been asked this question by my college director while I was bunking the class.My doubt is from Carrier Life time topic in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» CORRECT choice is (b) 1.510^10 Easy explanation: Ren=EnNT(fF (Et)) SUBSTITUTING the values, Ren=1.510^10.

Discussion

36.	Which of the following formulae doesn’t account for correct expression for J?(a) ρv(b) I/wd(c) σE(d) µHI got this question in semester exam.I'm obligated to ask this question of The Hall Effect topic in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The CORRECT OPTION is (d) µH Explanation: B=µH So, option d is correct option.

Discussion

37.	What is the velocity when the electric field is 5V/m and the magnetic field is 5A/m?(a) 1m/s(b) 25m/s(c) 0.2m/s(d) 0.125m/sThis question was addressed to me in a national level competition.Question is from The Hall Effect topic in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» CORRECT ANSWER is (a) 1m/s The EXPLANATION is: E=vxB v=E/B =5/5 =1m/s.

Discussion

38.	Calculate the diffusion current density when the concentration of electron varies from the 110^18 to 710^17 cm^-3 over a distance of 0.10 cm.D=225cm^2/s(a) 100 A/cm^2(b) 108 A/cm^2(c) 0.01A/cm^2(d) NoneThis question was addressed to me in a job interview.I'm obligated to ask this question of Diffusion topic in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» CORRECT choice is (B) 108 A/cm^2 The best explanation: J=eDdn/dx J=1.610^-19225(10^18-(710^17))/0.1 =108A/cm^2.

Discussion

39.	What is the voltage difference if the current is 1mA and length and area is 2cm and 4cm2 respectively?(ρ=2Ωm)(a) 0.025V(b) 25V(c) 0.25V(d) NoneThis question was addressed to me in a job interview.The origin of the question is Conductivity of a Semiconductor topic in division Conduction in Semiconductors of Electronic Devices & Circuits
Answer» RIGHT OPTION is (d) None For explanation I would say: V=IR R=ρl/(A)=22/4=100Ω V=1mA100 =0.1V.

Discussion

40.	At what condition, the rate of electron capture from the conduction band and the rate of the electron emission back into the conduction band must be equal?(a) Thermal equilibrium(b) At room temperature(c) T=250K(d) At boiling temperatureThe question was asked in a job interview.The doubt is from Carrier Life time topic in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The correct CHOICE is (a) Thermal EQUILIBRIUM The explanation: At thermal equilibrium, the electron capture RATE and the EMISSION rate will be same in the conduction BAND.

Discussion

41.	If excess charge carriers are created in the semiconductor then the new Fermi level is known as Quasi-Fermi level. Is it true?(a) True(b) FalseThis question was posed to me in exam.Enquiry is from Fermi Level in a Semiconductor having Impurities in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Correct ANSWER is (a) True Easiest EXPLANATION: Quasi-fermi LEVEL is defined as the change in the level of the Fermi level when the EXCESS chare carriers are added to the SEMICONDUCTOR.

Discussion

42.	Calculate the diffusion constant for the holes when the mobility of the holes is 400cm^2/V-s and temperature is 300K?(a) 1.035m m^2/s(b) 0.035m m^2/s(c) 1.5m m^2/s(d) 1.9m m^2/sThe question was asked in exam.The origin of the question is Diffusion topic in division Conduction in Semiconductors of Electronic Devices & Circuits
Answer» RIGHT ANSWER is (a) 1.035m m^2/s Best EXPLANATION: Dp=VTμn = (1.3810^-2330040010^-2)/ (1.610^-19) = 1.035m m^2/s.

Discussion

43.	Is resistivity is a function of temperature?(a) True(b) FalseThe question was posed to me in my homework.This intriguing question comes from Conductivity of a Semiconductor in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Right ANSWER is (a) True To elaborate: Resistance depends on the TEMPERATURE and the RESISTIVITY depends on the resistance, so now the resistivity depends on the temperature.

Discussion

44.	Which of the following expressions represent the Fermi probability function?(a) fF(E)=exp(-[E-EF]/KT)(b) fF(E)=exp(-[EF-E]/KT)(c) fF(E)=exp([E-EF]/KT)(d) fF(E)=exp(-[EF-E]/KT)This question was posed to me in my homework.Enquiry is from Electrons and Holes in Semiconductor in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The correct CHOICE is (b) FF(E)=exp(-[EF-E]/KT) The best explanation: It is the correct formula for the Fermi probability function.

Discussion

45.	What of the following conditions satisfies when the number of holes which are thermally generated is equal to the holes lost by recombination?(a) I≠0(b) dp/dt≠0(c) g=p/τ(d) g≠p/τThe question was asked in an interview.I need to ask this question from The Continuity Equation in division Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The CORRECT option is (c) g=p/τ For EXPLANATION I WOULD say: Under the equilibrium conditions, I will be ZERO and then the dp/dt will aso be equal to zero in the CONTINUITY equation. Then, g= p/τ is left which is option c.

Discussion

46.	Calculate the number of coulombs per second if the area is 4cm^2, recombination rate of hole is 1000 cm^-3/s and the differential length is 2mm.(a) 1.2810^-23(b) 1.2810^-22(c) 1.2810^-21(d) 1.2810^-20The question was posed to me in examination.The above asked question is from The Continuity Equation topic in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Right CHOICE is (B) 1.2810^-22 For explanation I would say: NUMBER of coulombs per SECOND= eAdxp/τ =1.610^-19410^-4210^-31000 =1.2810^-22.

Discussion

47.	Calculate the diffusion constant for the electrons when the mobility of the electrons is 325cm^2/V-s and temperature is 300K?(a) 0.85 m^2/s(b) 0.084 m^2/s(c) 0.58 m^2/s(d) 0.95 m^2/sI got this question during an interview.The doubt is from Diffusion topic in portion Conduction in Semiconductors of Electronic Devices & Circuits
Answer» Right CHOICE is (C) 0.58 m^2/s The EXPLANATION is: Dn=VTμn = (1.3810^-2330032510^-2)/ (1.610^-19) = 0.084 m^2/s.

Discussion

48.	Calculate the average random thermal energy at T=300K?(a) 0.038eV(b) 3.8eV(c) 38eV(d) 0.38eVThis question was addressed to me in class test.My query is from Conductivity of a Semiconductor in section Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The CORRECT option is (a) 0.038eV To explain: Average RANDOM thermal energy=3/2KT=0.038eV.

Discussion

49.	Does a semiconductor satisfy the ohm’s law?(a) True(b) FalseThe question was asked in an internship interview.My doubt stems from Conductivity of a Semiconductor in chapter Conduction in Semiconductors of Electronic Devices & Circuits
Answer» The CORRECT answer is (a) True For EXPLANATION I would say: V=IR J=σE I/A=σ(V/L) V=(L/ σA)I=(ρL)I/A=IR Thus, above EQUATION satisfies OHM’s law.

Discussion

50.	What is the value of the effective density of states function in the conduction band at 300k?(a) 310^19 cm^-3(b) 0.410^-19 cm^-3(c) 2.510^19 cm^-3(d) 2.510^-19 cm^-3I got this question in exam.My question is based upon Electrons and Holes in Semiconductor in portion Conduction in Semiconductors of Electronic Devices & Circuits
Answer» RIGHT ANSWER is (C) 2.510^19 cm^-3 Explanation: SUBSTITUTING the VALUES of mn=m0 ,h=6.62610^-34J/s ,k=1.3810^-23 and T=300K, we get Nc=2.510^19 cm^-3.

Discussion

Explore topic-wise InterviewSolutions in .

What is the SI unit of conductivity?(a) Ωm(b) (Ωm)-1(c) Ω(d) mThis question was posed to me by my college professor while I was bunking the class.The question is from Conductivity of a Semiconductor in portion Conduction in Semiconductors of Electronic Devices & Circuits

Do the Fermi energy level changes in a semiconductor?(a) True(b) FalseThis question was posed to me in my homework.I'd like to ask this question from Charge Densities in a Semiconductor impurities in chapter Conduction in Semiconductors of Electronic Devices & Circuits

At what temperature the donor states are completely ionized?(a) 0 K(b) ROOM(c) 300K(d) 900KI got this question during a job interview.The query is from Donor and Acceptor impurities in section Conduction in Semiconductors of Electronic Devices & Circuits

In which range of temperature, freeze out point begins to occur?(a) Higher range(b) Lower range(c) Middle range(d) NoneThis question was addressed to me in examination.The question is from Conductivity of a Semiconductor in section Conduction in Semiconductors of Electronic Devices & Circuits

What is the diffusion length for electrons when Dn=10cm^2/s and τn=40s?(a) 50cm(b) 25cm(c) 20cm(d) 15cmThe question was asked in my homework.Asked question is from The Continuity Equation topic in division Conduction in Semiconductors of Electronic Devices & Circuits

What does p/τ represent?(a) holes(b) time(c) holes per second lost(d) p per unit timeThe question was asked in my homework.This interesting question is from The Continuity Equation topic in portion Conduction in Semiconductors of Electronic Devices & Circuits

Which is the correct formula for the Jp?(a) Jp=qDdp/dx(b) Jp=pDdn/dx(c) Jp=-qDdp/dx(d) NoneI have been asked this question in a national level competition.This is a very interesting question from Diffusion in chapter Conduction in Semiconductors of Electronic Devices & Circuits

The opposite of ionization takes place at which temperature?(a) 0 K(b) ROOM(c) 300 K(d) 900KI have been asked this question by my school principal while I was bunking the class.Question is from Donor and Acceptor impurities in section Conduction in Semiconductors of Electronic Devices & Circuits

Calculate the Hall voltage when B=5A/m, I=2A, w=5cm and n=10^20.(a) 3.125V(b) 0.3125V(c) 0.02V(d) 0.002VI had been asked this question by my school teacher while I was bunking the class.My enquiry is from The Hall Effect topic in chapter Conduction in Semiconductors of Electronic Devices & Circuits

What does dn/dx represent?(a) Velocity gradient(b) Volume gradient(c) Density gradient(d) NoneThis question was addressed to me in an interview for internship.This intriguing question originated from Diffusion topic in chapter Conduction in Semiconductors of Electronic Devices & Circuits

Which of the following formulae doesn’t account for correct expression for J?(a) ρv(b) I/wd(c) σE(d) µHI got this question in semester exam.I'm obligated to ask this question of The Hall Effect topic in chapter Conduction in Semiconductors of Electronic Devices & Circuits

Is resistivity is a function of temperature?(a) True(b) FalseThe question was posed to me in my homework.This intriguing question comes from Conductivity of a Semiconductor in section Conduction in Semiconductors of Electronic Devices & Circuits

Calculate the average random thermal energy at T=300K?(a) 0.038eV(b) 3.8eV(c) 38eV(d) 0.38eVThis question was addressed to me in class test.My query is from Conductivity of a Semiconductor in section Conduction in Semiconductors of Electronic Devices & Circuits

Does a semiconductor satisfy the ohm’s law?(a) True(b) FalseThe question was asked in an internship interview.My doubt stems from Conductivity of a Semiconductor in chapter Conduction in Semiconductors of Electronic Devices & Circuits