Electronics Sheet (1) - Githubissues

YoussefLasheen commented 1 year ago

1. An atom consist of:

A. one nucleus and only one electron
B. one nucleus and one or more electrons
C. protons, electrons, and neutrons
D. answer b or c

2. The atomic number of silicon is:

A. 8
B. 14
C. 4

3. The atomic number of germanium is:

A. 32
B. 4
C. 8

4.The most widely used semiconductive material in electronic device is:

A. silicon
B. carbon
C. germanium D. copper

5. The energy band in which free electrons exist is the:

A. first band B. conduction band C. second band D. valence band

6. Electron-holes pairs are produced by:

A. ionization
B. thermal energy
C. recombination
D. doping

7. Recombination is when:

A. a crystal is formed
B. a positive and a negative ion bond together
C. an electron falls into a hole
D. a valence electron becomes a conduction electron

8. Each atom in a silicon crystal has:

A. no valence electrons because all are shared with others atoms
B. eight valence electrons because all are with other atoms
C. four valence electrons
D. four conduction electrons

9. The current in a semiconductor is produced by:

A. holes only
B. electrons only
C. both electrons and holes
D. negative ions

10. In an intrinsic semiconductor:

A. there are no free electrons
B. the free electrons are thermally produced
C. there are only holes
D. there are as many electrons as there are holes
E. answer b and d

11. A pure semiconductor behaves like an insulator at 00 K because:

A. There is no recombination of electrons with holes
B. Drift velocity of free electrons is very small
C. Free electrons are not available for current conduction
D. Energy possessed by electrons at that low temperature is almost zero

12. In semiconductor the forbidden energy gap lies:

A. Just below the conduction band
B. Just above the conduction band
C. Either above or below the conduction band
D. Between the valence band and conduction band

13. A semiconductor is formed by ……… bonds.

A. Covalent
B. Electrovalent
C. Co-ordinate
D. None of the above

14. The process of adding an impurity to an intrinsic semiconductor is called:

A. atomic modification
B. doping
C. recombination
D. ionization

15. A trivalent impurity is added to silicon to create:

A. germanium
B. an n-type semiconductor
C. a depletion region
D. a p-type semiconductor

16. When diode is forward-biased:

A. the only current is hole current
B. the only current is produced by majority carriers
C. the current is produced by both holes and electrons D. the only current is electron current

17. The purpose of a pentavalent impurity is to:

A. increase the number of free electrons B. create minority carriers C. reduce the conductivity of silicon D. increase the number of holes

18. Holes in an n-type semiconductor are:

A. minority carriers that are thermally produced B. majority carriers that are thermally produced C. minority carriers that are produced by doping
D. majority carriers that are produced by doping

19. A pn junction is formed by:

A. ionization
B. the boundary of a p-type and an n-type material
C. the recombination of electrons and holes
D. the collision of a proton and a neutron

20. The depletion region consists of:

A. nothing but minority carriers
B. positive and negative ions
C. no majority carriers
D. answer b and c

21. In a PN junction with no external voltage, the electric field between acceptor and donor ions is called:

A. Peak
B. Barrier
C. Threshold
D. Path

22. For a PN junction diode, the current in reverse bias may be:

A. Few miliamperes
B. Between 0.2 A and 15 A
C. Few amperes
D. Few micro or nano amperes

23. In a PN junction when the applied voltage overcomes the ........ potential, the diode current is large, which is known as .............

A. Depletion, negative bias
B. Reverse, reverse bias
C. Resistance, reverse bias
D. Barrier, forward bias

24. The term bias means:

A. a dc voltage is applied to control the operation of a device
B. neither a, b nor c
C. the ratio of majority carriers to minority carriers
D. the amount of current across a diode

25. In a reverse biased PN junction the current through the junction increases abruptly at:

A. 0.5 V
B. 1.1 V
C. 0.72 V
D. Breakdown voltage

26. Although current is blocked in reverse bias:

A. there is some current due to majority carriers
B. there is very small current due to minority carriers
C. there is an avalanche current

27. When a voltmeter is placed across a forward-biased diode, it will read a voltage approximately equal to:

A. the diode barrier potential
B. the bias battery voltage
C. the total
D. circuit voltage
E. 0 V

28. At room temperature N-type material will have....

A. More of electrons
B. More of holes
C. Equal number of electrons and holes

29. A forward biased pn junction diode has a resistance of the order of:

A. Ω
B. kΩ
C. MΩ
D. None of the above

30. A reverse biased pn junction has resistance of the order of:

A. Ω
B. kΩ
C. MΩ