Semiconductor Physics MCQ
Semiconductor Physics MCQ, Multiple Choice Questions on Semiconductor Physics, Gate Questions on Semiconductor Physics, Engineering MCQ, Electronics Device & Circuit MCQ, Semiconductor Physics Multiple Choice Questions
Multiple Choice Questions
Q.1. A semiconductor is formed by …….. bonds.
- covalent
- electrovalent
- co-ordinate
- none of the above
Answer: covalent
Q.2. A semiconductor has …….. temperature coefficient of resistance.
- positive
- zero
- negative
- none of the above
Answer: negative
Q.3. The most commonly used semiconductor is ……..
- germanium
- silicon
- carbon
- sulphur
Answer: silicon
Q.4. A semiconductor has generally …….. valence electrons.
- 2
- 3
- 6
- 4
Answer: 4
Q.5. The resistivity of pure germanium under standard conditions is about ……..
- 6 × 104 Ω cm
- 60 Ω cm
- 3 × 106 Ω cm
- 6 × 10−4 Ω cm
Answer: 60 Ω cm
Q.6. The resistivity of pure silicon is about ……..
- 100 Ω cm
- 6000 Ω cm
- 3 × 105 Ω cm
- 1.6 × 10− 8 Ω cm
Answer: 6000 Ω cm
Q.7. When a pure semiconductor is heated, its resistance ……..
- goes up
- goes down
- remains the same
- cannot say
Answer: goes down
Q.8. The strength of a semiconductor crystal comes from ……..
- forces between nuclei
- forces between protons
- electron-pair bonds
- none of the above
Answer: electron-pair bonds
Q.9. When a pentavalent impurity is added to a pure semiconductor, it becomes ……..
- an insulator
- an intrinsic semiconductor
- p-type semiconductor
- n-type semiconductor
Answer: n-type semiconductor
Q.10. Addition of pentavalent impurity to a semiconductor creates many ……..
- free electrons
- holes
- valence electrons
- bound electrons
Answer: free electrons
Q.11. A pentavalent impurity has …….. valence electrons.
- 3
- 5
- 4
- 6
Answer: 5
Q.12. An n-type semiconductor is ……..
- positively charged
- negatively charged
- electrically neutral
- none of the above
Answer: electrically neutral
Q.13. A trivalent impurity has …….. valence electrons.
- 4
- 5
- 6
- 3
Answer: 3
Q.14. Addition of trivalent impurity to a semiconductor creates many ……..
- holes
- free electrons
- valence electrons
- bound electrons
Answer: holes
Q.15. A hole in a semiconductor is defined as ……..
- a free electron
- the incomplete part of an electron pair bond
- a free proton
- a free neutron
Answer: the incomplete part of an electron pair bond
Q.16. The impurity level in an extrinsic semiconductor is about …….. of pure semiconductor.
- 10 atoms for 108 atoms
- 1 atom for 108 atoms
- 1 atom for 104 atoms
- 1 atom for 100 atoms
Answer: 1 atom for 108 atoms
Q.17. As the doping to a pure semiconductor increases, the bulk resistance of the semiconductor ……..
- remains the same
- increases
- decreases
- none of the above
Answer: decreases
Q.18. A hole and electron in close proximity would tend to ……..
- repel each other
- attract each other
- have no effect on each other
- none of the above
Answer: attract each other
Q.19. In a semiconductor, current conduction is due ……..
- only to holes
- only to free electrons
- to holes and free electrons
- none of the above
Answer: to holes and free electrons
Q.20. The random motion of holes and free electrons due to thermal agitation is called ……..
- diffusion
- pressure
- ionisation
- none of the above
Answer: diffusion
Q.21. A forward biased pn junction has a resistance of the ……..
- order of Ω
- order of kΩ
- order of MΩ
- none of the above
Answer: order of Ω
Q.22. 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 the above
Answer: +ve terminal to p and −ve terminal to n
Q.23. The barrier voltage at a pn junction for germanium is about ……..
- 3.5 V
- 3V
- zero
- 0.3 V
Answer: 0.3 V
Q.24. In the depletion region of a pn junction, there is a shortage of ……….
- acceptor ions
- holes and electrons
- donor ions
- none of the above
Answer: holes and electrons
Q.25. A reverse biased pn junction has ……..
- very narrow depletion layer
- almost no current
- very low resistance
- large current flow
Answer: almost no current
Q.26. A pn junction acts as a ……..
- controlled switch
- bidirectional switch
- unidirectional switch
- none of the above
Answer: unidirectional switch
Q.27. A reverse biased pn junction has resistance of the……..
- order of Ω
- order of kΩ
- order of MΩ
- none of the above
Answer: order of MΩ
Q.28. The leakage current across a pn junction is due to ……..
- minority carriers
- majority carriers
- junction capacitance
- none of the above
Answer: minority carriers
Q.29. When the temperature of an extrinsic semiconductor is increased, the pronounced effect is on ……..
- junction capacitance
- minority carriers
- majority carriers
- none of the above
Answer: minority carriers
Q.30. With forward bias to a pn junction, the width of depletion layer ……..
- decreases
- increases
- remains the same
- none of the above
Answer: decreases
Q.31. The leakage current in a pn junction is of the order of ……..
- A
- mA
- kA
- μA
Answer: μA
Q.32. In an intrinsic semiconductor, the number of free electrons ……..
- equals the number of holes
- is greater than the number of holes
- is less than the number of holes
- none of the above
Answer: equals the number of holes
Q.33. At room temperature, an intrinsic semiconductor has ……..
- many holes only
- a few free electrons and holes
- many free electrons only
- no holes or free electrons
Answer: a few free electrons and holes
Q.34. At absolute temperature, an intrinsic semiconductor has ……..
- a few free electrons
- many holes
- many free electrons
- no holes or free electrons
Answer: no holes or free electrons
Q.35. At room temperature, an intrinsic silicon crystal acts approximately as ……..
- a battery
- a conductor
- an insulator
- a piece of copper wire
Answer: an insulator