Explore topic-wise MCQs in Physical Electronics Devices and ICs.

This section includes 521 Mcqs, each offering curated multiple-choice questions to sharpen your Physical Electronics Devices and ICs knowledge and support exam preparation. Choose a topic below to get started.

51.

Find I1 and I2 in diagram shown below in terms of VS assume VT = 0.7 volt for all diode

A. None of the above
Answer» B.
Discussion
52.

Match List-I (Devices) with List-II (Property) and select the correct answer using the code given below the lists List-I (a) Silicon diode (b) Germanium diode (c) LED (d) PIN diode List-II 1. High frequency applications 2. Very low reverse bias saturation current 3. Low forward bias voltage drop 4. Cut-off wavelength Codes:

A. 1342
B. 2431
C. 1432
D. 2341
Answer» E.
Discussion
53.

A Si transistor has a thermal ratings, Tmax = 150 C and = 0 7 C/W. The power which this transistor could dissipate if the case could be maintained at 50 C is

A. 143 W
B. 59 W
C. 110 W
D. 85 W
Answer» B. 59 W
Discussion
54.

The emitter resistor RE bypassed by a capacitor CE

A. Reduces the voltage gain
B. Increases the voltage gain
C. Causes thermal runaway
D. Stabilizes the Q point
Answer» E.
Discussion
55.

When a diode is heavily doped (A) The zener voltage will be low (B) The avalanche voltage will be high (C) The depletion region will be thin (D) The leakage current will be low

A. Is due to majority carriers
B. Decreases with decreasing temperature
C. Is in mA or A range
D. None of these
Answer» D. None of these
Discussion
56.

A zener diode in the circuit shown in the figure below, has a knee current of 5 mA and a maximum allowed power dissipation of 300 mW. What are the minimum and maximum load currents that can be drawn safely from the circuit, keeping the output voltage V0 at 6 V?

A. 0 mA, 180 mA
B. 5 mA, 110 mA
C. 10 mA, 55 mA
D. 60 mA, 180 mA
Answer» D. 60 mA, 180 mA
Discussion
57.

A common collector amplifier uses a transistor whose h-paramters are hic = 900 , hfc = 25 and hrc = 1. If source and load resistances are 10 K and 500 respectively, the voltage gain of the amplifier is

A. 0 53
B. 0 93
C. 1 2
D. 2 3
Answer» B. 0 93
Discussion
58.

Match List-I (Diode type) with List-II (Important properties) and select the correct answer using the code given below the lists List-I (a) Zener Diode (b) Gunn Diode (c) Schottky Diode (d) Tunnel Diode List-II 1. Negative resistance device fabricated using semiconductors like Si, Ga, As, Ge etc. can be operated at a frequency of 10 GHz. 2. Quantum mechanical tunnelling with very thin depletions layers under reverse bias operated as a reference voltage sources.3. Negative conductance device, operates on the principle of transfer of electron from one region of conduction band to another. 4. Metal-semiconductor diode, have rectification properties. Codes:

A. 2431
B. 1342
C. 2341
D. 1432
Answer» D. 1432
Discussion
59.

A junction transistor with = 49 and ICO = ICBO = 1 A has IB = 10 A. The value of IC is given in A by

A. 441
B. 490
C. 539
D. 540
Answer» E.
Discussion
60.

Dynamic resistance of a diode varies as

A. I
B. I
C. I
D. I
Answer» C. I
Discussion
61.

Match List-I with List-II and select the correct answer using the code given below the lists List-I (a) Gunn Diode (b) Solar Cell (c) MOSFET (d) SCR List-II 1. Junctionless device 2. Single junction device 3. Double junction device 4. Triple junction device Codes:

A. 1234
B. 3412
C. 1432
D. 3214
Answer» B. 3412
Discussion
62.

In a transistor hfe = 50, hie = 830 , hoe = 10 4. Its output resistance when used in CB configuration is about

A. 2 M
B. 500 K
C. 2 5 M
D. 780 K
Answer» C. 2 5 M
Discussion
63.

For the given transistors 1. Point contact transistor 2. Bipolar junction transistor 3. MOS field effect transistor 4. Junction field effect transistor The correct sequence of these transistors in the increasing order of input impedance is

A. 1, 2, 4, 3
B. 1, 2, 3, 4
C. 2, 1, 3, 4
D. 2, 1, 4, 3
Answer» E.
Discussion
64.

The circuit given below employs a silicon transistor with the = 50. The value of biasing resistance Rb for maximum symmetrical swing at the output should be

A. 120 K
B. 78 K
C. 193 K
D. 122 K
Answer» D. 122 K
Discussion
65.

If the transistors in figure have high values of and a VBE of 0.65V, the current I flowing through the 2 k resistance will be

A. 1 mA
B. 3.33 mA
C. 0
D. 5 mA
Answer» B. 3.33 mA
Discussion
66.

For the 2N 338 transistor, the manufacturing specifies Pmax = 100 mW and 25 C free air temperature and the maximum junction temperature Tjmax = 125 C, its thermal resistance is

A. 10 C/W
B. 100 C/W
C. 1000 C/W
D. 10,000 C/W
Answer» D. 10,000 C/W
Discussion
67.

In an Abrupt pn-junction the doping concentrations on the p-side and n-side are NA = 1017/cm3 and ND = 1016/cm3 respectively. It the pn-junction is reverse biased and total depletion width is 3 m. The depletion width on p-side will be

A. 0.3 m
B. 0.27 m
C. 2.7 m
D. None of these
Answer» C. 2.7 m
Discussion
68.

If = 0 98, ICO = 6 A and IB = 100 A for a transistor, then the value of IC will be

A. 2 3 mA
B. 3 1 mA
C. 4 6 mA
D. 5 2 mA
Answer» E.
Discussion
69.

The JFET in the circuit shown in figure has an IDSS = 10 mA and Vp = 5 V. The value of the resistance RS for a drain current IDS = 6.4 mA is (select the nearest value)

A. 150 ohm
B. 470 ohm
C. 560 ohm
D. 1 kilo ohm
Answer» B. 470 ohm
Discussion
70.

If the amount of impurity, either p-type or n-type, added to the intrinsic is controlled to part in one million, the conductivity of the sample

A. Increases by a factor of 10
B. Increases by a factor of 10
C. Decreases by a factor of 10
D. Is not affected at all
Answer» B. Increases by a factor of 10
Discussion
71.

The voltages at V1 and V2 of the arrangement shown in the figure will be respectively

A. 6 V and 5.4 V
B. 5.4 V and 6 V
C. 3 V and 5.4 V
D. 6 V and 3 V
Answer» B. 5.4 V and 6 V
Discussion
72.

In a semiconductor, fermi level is proportional to

A. N
B. N
C.
D. N
E. N
Answer» D. N
Discussion
73.

If = 0 995, IE = 10 mA and ICO = 0 5 A, then ICEO will be

A. 25 A
B. 100 A
C. 10 1 A
D. 10 5 A
Answer» C. 10 1 A
Discussion
74.

In a Schmitt trigger using OP amplifiers the output is limited by diode clipper to V0 = 8 volts. The positive input terminal voltage V+ = V0, where = 1 / 8. The signal Vs is applied to V . The following statements (1) to (4) are made regarding Vs and V+ (1) For Vs negative and rising V+ = + 1 (2) For Vs positive and decreasing V+ = + 1(3) For Vs decreasing through zero value V+ = + 1 (4) For Vs increasing though zero value V+ = + 1 Of these statements, the true statements are

A. 1 and 3
B. 2 and 3
C. 1 and 4
D. None of these statements
Answer» D. None of these statements
Discussion
75.

For a PNP transistor, = R = 0 9 and ICO = 10 A the value of ICEO will be

A. 15 2 A
B. 52 6 A
C. 72 5 A
D. 1 00 A
Answer» E.
Discussion
76.

Determine ID.

A. 0 mA
B. 1.86 mA
C. 2.036 mA
D. 2.143 mA
Answer» C. 2.036 mA
Discussion
77.

Select the correct output (V0) wave shape for a given input (Vi) in clamping network shown below

A. (A)
B. (B)
C. (C)
D. (D)
Answer» E.
Discussion
78.

An n-channel JFET having a pinch-off voltage VP of 5V shows a transconductance gm of 1 mA/V when the applied gate to source voltage is 3V. Its maximum transconductance in (mA/V) will be

A. 1 5
B. 2 0
C. 2 5
D. 3 0
Answer» D. 3 0
Discussion
79.

A voltage signal 10 sin t is applied to the circuit with ideal diodes, as shown in figure. The maximum and minimum values of the output waveform Vout of the circuit are respectively

A. + 10 V and 10 V
B. + 4 V and 4 V
C. + 7 V and 4 V
D. + 4 V and 7 V
Answer» E.
Discussion
80.

What is the voltage measured from the negative terminal of C4 to the negative terminal of the transformer? Given Vm = 5V.

A. 10 V
B. 50 V
C. 25 V
D. 20 V
Answer» E.
Discussion
81.

The drain current of a MOSFET in saturation is given by ID = K (VG S VT)2 where K is a constant. The magnitude of the transconductance gm is

A. 2K (V
B. V
C. )
Answer» C. )
Discussion
82.

A silicon semiconductor sample at T = 300 K is doped with phosphorus atoms at a concentrations of 1015 cm 3. The position of the Fermi level with respect to the intrinsic Fermi level is

A. 0.3 eV
B. 0.2 eV
C. 0.1 eV
D. 0.4 eV
Answer» B. 0.2 eV
Discussion
83.

Determine V2.

A. 3.201 V
B. 0 V
C. 4.3 V
D. 1.371 V
Answer» E.
Discussion
84.

In figure, a silicon diode is carrying a constant current of 1 mA. When the temperature of the diode is 20 C, VD is found to be 700 mV. If the temperature raises to 40 C, VD becomes approximately equal to

A. 750 mV
B. 650 mV
C. 680 mV
D. 700 mV
Answer» C. 680 mV
Discussion
85.

A diode is in the _____ state if the current established by the applied sources is such that its direction matches that of the arrow in the diode symbol, and VD ? 0.7 V for Si and VD? 0.3 V for Ge.

A. Off
B. On
C. Neutral
D. Quiescent
Answer» C. Neutral
Discussion
86.

The cross sectional area of silicon bar is 100 m2. The length of bar is 1 mm. The bar is doped with arsenic atoms. The resistance of bar is

A. 2.58 m
B. 11.36 k
C. 1.36 m
D. 24.8 k
Answer» C. 1.36 m
Discussion
87.

In a step graded reverse biased junction. The width of the depletion layer varies as (where VJ is the magnitude of the junction potential)

A.
B. V
C.
D. V
E. J
Answer» B. V
Discussion
88.

The transistor in the amplifier shown has following parameters: hfe = 100, hi e = 2 k , hre = 0, hoe = 0.05 m mho. C is very large. The output impedance is

A. 20 k
B. 16 k
C. 5 k
D. 4 k
Answer» B. 16 k
Discussion
89.

The diffusion capacitance of a forward biased p+ n junction diode with a steady current I depends on

A. Width of the depletion region
B. Mean lifetime of the holes
C. Mean lifetime of the electrons
D. Junction area
Answer» C. Mean lifetime of the electrons
Discussion
90.

A silicon sample doped n-type at 1018 cm 3 have a resistance of 10 . The sample has an area of 10 6 cm2 and a length of 10 m. The doping efficiency of the sample is ( a = 800 cm2/ V s)

A. 43.2%
B. 78.1%
C. 96.3%
D. 54.3%
Answer» C. 96.3%
Discussion
91.

The quiescent collector current IC of a transistor is increased by changing the biasing resistance. As a result gm will

A. Not be affected
B. Decrease
C. Increase
D. Increase or decrease depending on bias stability
Answer» D. Increase or decrease depending on bias stability
Discussion
92.

In any p-n junction, the transition capacitance CT varies as

A. W
B. W
C.
D.
E. where W is the width of the depletion layer.
Answer» D.
Discussion
93.

The space charge in a pn-junction consists of (i) Electrons (ii) Holes (iii) Ionized acceptors (iv) Ionized donors The correct option is

A. (i) and (ii) only
B. (i) and (iii) only
C. (ii) and (iv) only
D. (iii) and (iv) only
Answer» E.
Discussion
94.

In the given circuit, D1 is an ideal germanium diode and D2 is a silicon diode having its cut-in voltage as 0 7 V, forward resistance as 20 and reverse saturation current (Is) as 10 nA. What are the values of I and V for this circuit, respectively?

A. 60 mA and 0 V
B. 50 mA and 0 V
C. 53 mA and 0 7 V
D. 44 mA and 1 58 V
Answer» B. 50 mA and 0 V
Discussion
95.

Depth of focus (DOF) in photolithography is given by

A. NA
B. 2 / (NA)
C. (NA)
D. 2 (NA)
Answer» E.
Discussion
96.

Determine ID1.

A. 0 mA
B. 29.40 mA
C. 14.70 mA
D. 14.09 mA
Answer» B. 29.40 mA
Discussion
97.

Determine ID2.

A. 6.061 mA
B. 0.7 mA
C. 3.393 mA
D. 3.303 mA
Answer» E.
Discussion
98.

Determine the current through each diode if E1 = E2 = 0V.

A. 4.65 mA
B. 9.3 mA
C. 18.6 mA
D. 0.7 mA
Answer» C. 18.6 mA
Discussion
99.

Match List I with List II and select the correct answer using the codes given below the lists List - I (Device) List - II (Biasing mode) A.LED 1.Forward bias B.Zener2. Reverse bias C.Varactor D. SCR

A. 1122
B. 1212
C. 1221
D. 2211
Answer» D. 2211
Discussion
100.

The parameters of an FET are gm = 3 mA/V, id = 30 k. RL = 3 k as a source follower load. The output impedance is given by

A. 333 ohm
B. 3 k ohm
C. 27 k ohm
D. 300 ohm
Answer» E.
Discussion