MCQ on Semiconductor Material
MCQ on Semiconductor Material, Multiple Choice Questions on Semiconductor Material, Engineering Physics MCQ, Engineering MCQ, Electronics Device & Circuit MCQ, Semiconductor Physics Multiple Choice Questions
Multiple Choice Questions
Q.1. Which of the following, has the lowest temperature coefficient of resistivity.
Alum Silver, Copper, Gold, Aluminium
- Copper
- Silver
- Gold
- Aluminium
Answer: Gold
Q.2. In a metal
- The electrical conduction is by electrons and holes
- With rise in temperature, the conductivity decreases
- The conduction band is empty
- There is a small energy gap between the two bands
Answer: With a rise in temperature, the conductivity decreases
Q.3. The forbidden energy gap in semiconductors:
- lies just below the valence band
- is the same as the valence band
- lies just above the conduction band
- lies between the valence band and the conduction band
Answer: lies between the valence band and the conduction band
Q.4. The conduction band of a semiconductor material may be
- completely filled
- partially filled
- empty
- none
Answer: partially filled
Q.5. The energy band which possesses the free electrons is called:
- valence band
- conduction band
- forbidden band
- none of these
Answer: conduction band
Q.6. Which of the following behaves as an insulator.
- Diamond
- Germanium
- Silicon
- Silver
Answer: Diamond
Q.7. The unit of mobility of charge carriers is
- m2/volt-sec
- m/volt-sec2
- m3/volt-sec
- m/volt-sec
Answer: m2/volt-sec
Q.8. A semiconductor is electrically neutral because it has:
- no majority carriers
- no minority carriers
- no free carriers
- equal number of positive and negative carriers
Answer: an equal number of positive and negative carriers
Q.9. An intrinsic semiconductor at absolute zero temperature
- has large number of holes
- has a few hole and same number of electrons
- acts as an insulator
- acts as metallic character
Answer: acts as an insulator
Q.10. When the temperature of an intrinsic semiconductor is increased
- resistance of semiconductor is also increased
- conductivity is decreased
- energy of atoms is increased
- holes are created
Answer: energy of atoms is increased
Q.11. A doner-type impurity
- is used to obtain a p-type semiconductor
- is used to obtain a N-type semiconductor
- must possess three valence electrons
- cannot be used in silicon crystals
Answer: is used to obtain an N-type semiconductor
Q.12. If a small amount of antimony is added to Ge
- the resistance is increased
- Ge will become a p-type semi-conductor
- antimony becomes an acceptor impurity
- there will be no more free electrons than holes in a semiconductor
Answer: there will be no more free electrons than holes in a semiconductor
Q.13. In an N-type semiconductor, the concentration of minority carriers mainly depends upon
- doping technique
- number of donor atoms
- temperature of material
- quality of intrinsic materials Ge or Si
Answer: temperature of material
Q.14. In a P-type semiconductor, majority carriers are
- holes
- electrons
- both
- none of the above
Answer: holes
Q.15. Which of the following atoms can be used as a p-type impurity
- Boron
- Arsenic
- Antimony
- Phosphorus
Answer: Boron
Q.16. In an intrinsic semiconductors, the Fermi level lies:
- in the middle of conduction band (CB) and valence band (VB)
- near CB
- near VB
- none of these
Answer: in the middle of CB and VB
Q.17. 10-9 ohm-m is the resistivity of
- Aluminium
- Sodium
- Bismuth
- Nickel
Answer: Nickel
Q.18. Due to the illumination of light, the electron and hole concentrations in a heavily doped n-type semiconductor, increase by Δn and Δp respectively. If ni is the intrinsic concentration, then
- \Delta n < \Delta p
- \Delta n > \Delta p
- \Delta n = \Delta p
- \Delta n \times \Delta p = n_{i}^{2}
Answer: \Delta n \times \Delta p = n_{i}^{2}
Q.19. The current density Jo of electrons through any conductor carrying current is given by:
- J_{0}=\frac{ne\tau E}{m}
- J_{0}=\frac{ne\tau E^{2}}{m}
- J_{0}=\frac{ne^{2}\tau E}{m}
- J_{0}=\frac{e^{2}\tau E}{m}
Answer: J_{0}=\frac{ne^{2}\tau E}{m}
Q.20. An element used in semiconductors whose atoms have three valence electrons is
- Germanium
- A donor
- An acceptor
- Silicon
Answer: An acceptor
Q.21. The Hall coefficient RH is defined by
- R_{H}=\frac{V_{H}.t}{B}
- R_{H}=\frac{V_{H}B}{It}
- R_{H}=\frac{V_{H}t}{B}
- R_{H}=\frac{V_{H}t}{BI}
Answer: R_{H}=\frac{V_{H}t}{BI}
Q.22. The probability of occupation F(E) of an energy level E by an electron is given by
- F(E)=[1+e^{(E-E_{F})}/kT]
- F(E)=\frac{1}{1+e^{(E_{F}-E)}/kT}
- F(E)=\frac{1}{1+e^{(E-E_{F})}/kT}
- F(E)=\frac{1}{1-e^{(E-E_{F})}/kT}
Answer: F(E)=\frac{1}{1+e^{(E-E_{F})}/kT}
Q.23. For high conductivity and large temperature coefficient
- Pure metals are chosen
- Slightly impure materials are used
- Alloys are used
- Super-conductors are used
Answer: Pure metals are chosen
Q.24. The potential barrier at a pn junction is established due to the charge on either side of the Junction. These charges are
- majority carriers
- minority carriers
- both a and b
- donor and acceptor ions
Answer: donor and acceptor ions
Q.25. In a PN junction, holes diffuse from the p-region to the n-region because
- they move across the junction by the potential diffierence
- free electron available in the n-region attract them
- the holes concentration in the p-region is greater as compared to n-region
- all of these
Answer: the holes concentration in the p-region is greater as compared to n-region
Q.26. In a crystal diode, the barrier potential offers opposition to only
- free electrons in n-region
- holes in p-region
- majority carriers in both regions
- minority carriers in both regions
Answer: majority carriers in both regions
Q.27. When a reverse bias is applied to a crystal diode, it
- raises the potential barrier
- lowers the potential barrier
- increases the majority-carrier current greatly
- none of these
Answer: raises the potential barrier
Q.28. At reverse bias, the number of minority carriers crossing the junction of a diode depends primarily on the
- concentration of doping impurities
- rate of thermal generation of electron-hole pairs
- magnitude of the potential barriers
- all of these
Answer: all of these
Q.29. When a forward bias is applied to a crystal diode, it
- raises the potential barrier
- lowers the potential barrier
- reduces the majority-carrier current to zero
- none of these
Answer: lowers the potential barrier
Q.30. Avalanche breakdown in a crystal diode occurs when
- the potential barrier is reduced to a zero
- forward current exceeds a certain value
- reverse bias exceeds a certain value
- all of these
Answer: reverse bias exceeds a certain value