11. The depletion region or space charge region or transition region in a semiconductor P-N junction diode has
a) electron and holes.
b) positive ions and electrons.
c) positive ions and negative ions.
d) no ions, electron or holes.
ans. c
12. In a p+ n junction diode under reverse bias, the magnitude of electric field is maximum at
a) the edge of the depletion region on the p-side.
b) the edge of the depletion region on the n-side.
c) the p+n junction.
d) the centre of the depletion region on the n-side.
ans. c
13. A p-n junction has a built-in potential of 0.8 V. The depletion layer width at a reverse bias of 1.2V is the 2 micrometer. For a reverse bias of 7.2V , the depletion layer width will be
a) 4 micrometer
b) 4.9 micrometer
c) 8 micrometer
d) 12 micrometer
ans. a
14. At 300 K for a diode current of 1mA , a certain germanium diode requires a forward bias of 0.1435 V, whereas a certain silicon diode requires a forward bias of 0.718 V, Under the conditions stated above , the closest approximation of the ratio of reverse saturation current in germanium diode to that in silicon diode is
a) 1
b) 5
c) 4 x 10³
d) 8 x 10³
ans. c
15. A silicon PN junction at a temperature of 20⁰C has a reverse saturation current of 10 pico-Amperes (pA). The reverse saturation current at 40⁰C for same bias is approximately
a) 30 pA
b) 40 pA
c) 50 pA
d) 60 pA
ans. b
16. Which of the following is not associated with a p-n junction ?
a) Junction Capacitance
b) Charge Storage-Capacitance
c) Depletion Capacitance
d) Channel Length Modulation.
ans. d
17. As the temperature is increased, the voltage across a diode carrying a constant current
a) increases
b) decreases
c) remains constant.
d) may increase or decrease depending on the doping levels in the junction.
ans. b
18. Choose proper substitutes of X and Y to make the following statement correct. Tunnel diode and Avalanche diode are operated in X bias and Y bias respectively
a) X- reverse ,Y-reverse
b) X-reverse, Y -forward
c) X-forward, Y- reverse
d) X-forward, Y-forward
ans. c
19. Consider the following assertions.
S1- For zener effect to occur, a very abrupt junction is required.
S2- For quantum tunneling to occur , a very narrow energy barrier is required.
which of the following is correct?
a) Only S2 is true.
b) S1 and S2 are both true but S2 is not a reason for S1
c) S1 and S2 are both true and S2 is a reason for S1.
d) Both S1 and S2 are false.
ans. a
20. A dc power supply has a no-load voltage of 30 V, and a full-load voltage of 25 V at a full load-current of 1A. Its output resistance and load regulation , respectively are
a) 5 ohm and 20 %
b) 25 ohm and 20%
c) 5 ohm and 16.7%
d) 25 ohm and 16.7 %
ans. b
a) electron and holes.
b) positive ions and electrons.
c) positive ions and negative ions.
d) no ions, electron or holes.
ans. c
12. In a p+ n junction diode under reverse bias, the magnitude of electric field is maximum at
a) the edge of the depletion region on the p-side.
b) the edge of the depletion region on the n-side.
c) the p+n junction.
d) the centre of the depletion region on the n-side.
ans. c
13. A p-n junction has a built-in potential of 0.8 V. The depletion layer width at a reverse bias of 1.2V is the 2 micrometer. For a reverse bias of 7.2V , the depletion layer width will be
a) 4 micrometer
b) 4.9 micrometer
c) 8 micrometer
d) 12 micrometer
ans. a
14. At 300 K for a diode current of 1mA , a certain germanium diode requires a forward bias of 0.1435 V, whereas a certain silicon diode requires a forward bias of 0.718 V, Under the conditions stated above , the closest approximation of the ratio of reverse saturation current in germanium diode to that in silicon diode is
a) 1
b) 5
c) 4 x 10³
d) 8 x 10³
ans. c
15. A silicon PN junction at a temperature of 20⁰C has a reverse saturation current of 10 pico-Amperes (pA). The reverse saturation current at 40⁰C for same bias is approximately
a) 30 pA
b) 40 pA
c) 50 pA
d) 60 pA
ans. b
16. Which of the following is not associated with a p-n junction ?
a) Junction Capacitance
b) Charge Storage-Capacitance
c) Depletion Capacitance
d) Channel Length Modulation.
ans. d
17. As the temperature is increased, the voltage across a diode carrying a constant current
a) increases
b) decreases
c) remains constant.
d) may increase or decrease depending on the doping levels in the junction.
ans. b
18. Choose proper substitutes of X and Y to make the following statement correct. Tunnel diode and Avalanche diode are operated in X bias and Y bias respectively
a) X- reverse ,Y-reverse
b) X-reverse, Y -forward
c) X-forward, Y- reverse
d) X-forward, Y-forward
ans. c
19. Consider the following assertions.
S1- For zener effect to occur, a very abrupt junction is required.
S2- For quantum tunneling to occur , a very narrow energy barrier is required.
which of the following is correct?
a) Only S2 is true.
b) S1 and S2 are both true but S2 is not a reason for S1
c) S1 and S2 are both true and S2 is a reason for S1.
d) Both S1 and S2 are false.
ans. a
20. A dc power supply has a no-load voltage of 30 V, and a full-load voltage of 25 V at a full load-current of 1A. Its output resistance and load regulation , respectively are
a) 5 ohm and 20 %
b) 25 ohm and 20%
c) 5 ohm and 16.7%
d) 25 ohm and 16.7 %
ans. b
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