Revision:-

(Transistor)
1) The majority charge carriers in an NPN transistors are ……………
(a) Electrons. (b) Holes. (c) Trivalent atoms. (d) Pentavalent atoms.
2) In an NPN transistor operating in saturated mode, the output voltage VCE is ……….
(a) greater than 2VBE. (b) between 2VEB and VBE.
(c) less than VBE. (d) equal to VBE.
3) NPN transistor are preferred over PNP transistors because they have ……………..
(a) high mobility of holes (b) equal to mobility of holes (c) low mobility of holes
(d) higher mobility of electrons than the mobility of holes in p-n-p transistors
4) In a transistor, the ______________ is moderately doped and largest in size.
(a) emitter. (b) base (c) junction (d) collector
5) In a transistor the _________ is of moderate size and heavily doped.
(a) emitter. (b) junction (c) base (d) collector
6) for a transistor, β = 100. The value of α is ___________
(a) 1.01 (b) 0.99 (c) 100 (d) 0.01
7) if α-current gain of a transistor is 0.98. What is the value of β-current gain of the transistor?
(a) 0.49 (b) 49 (c) 4.9 (d) 5
8) In the active region ,The emitter-base junction of a transistor is ___________ biased while the
collector-base junction is __________biased.
(a) reverse, forward (b) reverse, reverse
(c) forward, forward (d) forward, reverse
9) The emitter of a transistor is ________________ doped.
(a) of moderate size and lightly (b) of moderate size and heavily
(c) very thin and heavily (d) very thin and lightly
10) The number of depletion layers in a transistor is ……………
(a) 4 (b) 3 (c) 1 (d) 2
11) The base of a transistor is ……..………....... doped.
(a)heavily. (b) moderately (c) lightly (d) none of the above
12) The collector of a transistor is ………….….. doped.
(a)heavily. (b) moderately (c) lightly (d) none of the above
13) The emitter of a transistor is …………….… doped
(a)heavily. (b) moderately (c) lightly (d) none of the above
14) A transistor is a …………… operated device.
(a) current (b) voltage
(c) both voltage and current (d) none of the above
15( A the temperature of a transistor goes up, the base-emitter resistance ……………
(a) decreased. (b) increased. (c) remains the same.
(d) none of the above.
16) With the positive probe on an NPN base, an ohmmeter reading between the other transistor
terminals should be ……
(a) open. (b) infinite. (c) low resistance. (d) high resistance.
17) To operate properly, a transistor’s base-emitter junction must be forward biased with reverse
bias applied to which junction?
(a) collector-emitter (b) base-collector (c) base-emitter (d) collector-base
18) A transistor may be used as a switching device or as a ………….
(a) fixed resistor (b) tuning device (c) rectifier (d) variable resistor
19) Most of the electrons in the base of an NPN transistor flow …………
(a) out of the base lead. (b) into the collector.
(c) into the emitter. (d) into the base supply.
20) In a transistor, collector current is controlled by ………..
(a) collector voltage (b) base current
(c) collector resistance (d) all of the above
21) The doped region in a transistor are ________
(a) Emitter and Collector (b) Emitter and Base
(c) Collector and Base (d) Emitter, Collector and Base
22) In an NPN transistor, the arrow is pointed towards_________
(a) the collector (b) the base
(c) depends on the configuration (d) the emitter
23) In the saturated region, the transistor acts like a_________
(a) poor transistor (b) amplifier
(c) open switch (d) closed switch
24) When does the transistor act like an open switch?
(a) cut off region (b) inverted region
(c) saturated region (d) active region
25) Most of the majority carriers from the emitter ………………..
(a) recombine in the base (b) recombine in the emitter
(c) pass through the base region to the collector (d) none of the above
 Solution:-
1 A
2 C
3 D
4 D
5 A
6 B
7 B
8 D
9 B
10 D
11 C
12 B
13 A
14 A
15 A
16 C
17 D
18 D
19 B
20 B
21 D
22 D
23 D
24 A
25 C

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