MCQ
41. Process of adding impurities to semiconductor is called-
ব্যাখ্যা: The process of adding controlled inpurities to a semiconductor is known as "doping" The amount of impurity, or dopant, added to as intrinsic (pure) semiconductor varies its level of conductivity.
mixing
refining
diffusing
doping
42. What is the full name of LCD?
Light control diode .
Light crystal display.
Liquid crystal diode.
Liquid crystal display.
43. Which one is the smallest region in a transistor?
ব্যাখ্যা: The base region of a BJT transistor is very thin and is lightly doped with current carries. It is the region of a transistor which has opposite polarity charge carries from the emitter and the collector regions.
base
collector
emitter
both (a) and (b)
44. When transistor is used as an amplifier, it is operated in the:
Cut off region
Saturation region
Active region
Both a and b
45. Transistor biasing represents --conditions.
ac
both ac & dc
dc
none
46. Half-wave rectifier- maximum efficiency--%
25
50
40.6
81.2
47. Emitter follower is used for--
Impedance matching
Current gain
Voltage gain
None of the above
48. If a power supply has no-load and full-load voltages of 30V and 25V respectively, then the percentage voltage regulation is:
10%
20%
15%
25%
49. The most commonly used semiconductor is-
germanium
carbon
sulphur
silicon
50. RC coupling is used for---amplification.
voltage
power
current
none
51. At what relgon a transistor operates --
Artlive
Saturatioit
Cut off
None
52. A PN junction acts as a--
ব্যাখ্যা: The PN junction is conduct with forward bias only. It means they conduct in only one direction (Current flows from P to N) That's why PN Junction acts as unidirectional twitch
unidirectional switch
bidirectional switch
controlled switch
none of the above
53. The maximum efficiency of a half-wave diode rectifier is --
50%
25%
40.0%
81.2%
54. The point of intersection of de and ac load lines is called-
saturation
operating
cut off
none of these
55. If, line frequency is 50 Hz, then output (Hz) of a bridge rectifier is-
ব্যাখ্যা: Output frequency of bridge rectifier is twice the input frequency. Full wave bridge rectifier, 25,2x50=100H
25
100
50
None
56. Class-B power amplifier- miximum collector efficiency কত %
25
78.5
50
60
57. In an LC oscillator, the frequency of oscillation is:
Proportional to LC
Proportional to square root of LC
Inversely proportional to the square root of LC
Independent of the value of LC
58. A pn junction acts as a-
ব্যাখ্যা : The PN junction is conduct with forward bias only. It means they conduct in only one direction (Current flows from P to N). That's why PN Junction acts as unidirectional switch.
unidirectional switch.
bidirecctional switch.
controlled switch.
both unidirectional and bidirectional.
59. For highest power gain, one would use-- configuration.
ব্যাখ্যা: For highest power gain, CE configuration is used. In CE configuration, biasing capacitor is used to balance the operating point to obtain highest power gain
CE
CB
CC
none of these
60. When there is no forbidden region between the conductance band and valence band, the substance is called:
Semiconductor.
conductor
superconductor
insulator