Explore topic-wise MCQs in Engineering.

This section includes 9294 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.

101.

A first order system will never be able to give a __________ response band stopband passall pass Choose the correct option

A. 1, 2, 3 true
B. 1 and 3 true, 2 false
C. 1, 2 are true 3 is false
D. 1, 2 are false, 3 is true
Answer» D. 1, 2 are false, 3 is true
Discussion
102.

In the given figure the ratio T/d is the duty factor.

A. True
B. False
Answer» C.
Discussion
103.

The amplitude of a pair of composite sinusoidal signal y(n) = x1(n) + x2(n) with x1(n) = sin (5pn) x2(n) = 3 sin (5pn) is __________ .

A. 2
B. 3
C. 4
D. 1
Answer» B. 3
Discussion
104.

For a = - 1, find the value of V2

A.
B. 0
C. V
D. <sub>1</sub>
E. none of the above
Answer» C. V
Discussion
105.

A n-channel JFET has IDSS = 2 mA, Gate to source voltage VGS = - 2 V and trans-conductance is 0.5 mW then pinch-off voltage is __________ .

A. - 2 V
B. 2 V
C. - 4 V
D. 4 V
Answer» D. 4 V
Discussion
106.

In the circuit below, delay of the EXOR and ANDLogic gates are 20 s and 10 s respectively, then the wave y' and y (with initial condition y = 1) will be :

A. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/4-788-45-3.png">
B. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/4-788-45-4.png">
C. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/4-788-45-5.png">
D. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/4-788-45-6.png">
Answer» C. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/4-788-45-5.png">
Discussion
107.

A unity-feedback control system has the open loop transfer function . If the input system is a unit ramp, the steady state error will be

A. 0
B. 0.5
C. 2
D. infinity
Answer» D. infinity
Discussion
108.

For a given voltage, four heating coils will produce maximum heat when connected

A. all in parallel
B. all in series
C. with two parallel pairs in series
D. one pair in parallel with the other two in series
Answer» B. all in series
Discussion
109.

The antenna current of an AM transmitter is 8 A, when only the carrier is sent, but it increases to 8.93 A when the carrier is modulated by a single sine wave. Determine the antenna current when the percent of modulation changes to 0.8

A. 9.19 A
B. 9.91 A
C. 10.56 A
D. 8.61 A
Answer» B. 9.91 A
Discussion
110.

If the system T.F. is The differential equation representing the system is

A. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/2-756-44-2.png">
B. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/2-756-44-3.png">
C. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/2-756-44-4.png">
D. none of these
Answer» D. none of these
Discussion
111.

Denominator polynomial of a transfer function of certain network is: s3 + s2 + 2s + 24 Then the network is:

A. stable
B. oscillatory
C. unstable
D. depends on numerator polynomial
Answer» D. depends on numerator polynomial
Discussion
112.

Consider the signal flow graph shown in figure below. The gain is :

A. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/16-02-8-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/16-02-8-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/16-02-8-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/16-02-8-4.png">
Answer» D. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/16-02-8-4.png">
Discussion
113.

During transmission over a communicate channel, bit errors occur independently with probability . If a block of 3 bits are transmitted, the probability of at most one bit error is equal to

A. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/11-03-40-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/11-03-40-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/11-03-40-3.png">
D. none
Answer» E.
Discussion
114.

When phase-lag compensation is used in a system, then gain cross over frequency, bandwidth and undamped frequency are respectively

A. Increased, Increased, Increased
B. Increased, Increased, Decreased
C. Increased, Decreased, Decreased
D. Decreased, Decreased, Decreased
Answer» E.
Discussion
115.

The gradient of any scalar field always yields __________ .

A. a solenoidal field
B. a conservative field
C. an irrotational field
D. none of these
Answer» C. an irrotational field
Discussion
116.

In a flash type ADC, employing 15 comparators resolution with 10 volts reference; is expected to be :

A. 0.625 V
B. 0.656 V
C. 0.525 V
D. insufficient data
Answer» B. 0.656 V
Discussion
117.

Find 'X' in the circuit below :f1(A, B, C, D) = (6, 7, 13, 14);f2(A, B, C, D) = (3, 6, 7);f3(A, B, C, D) = (5, 6, 7, 14, 15)

A. <span class="symbol">p</span>
B. (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15)
C. 0
D. (14)
E. 1
Answer» D. (14)
Discussion
118.

Consider the common emitter amplifier shown below with the following circuit parameters: = 100, gm = 0.3861 A/V, r0 = rp = 259 , Rs = 1 k , RB = 93 k , RC = 250 , RL = 1 kW, C1 = and C2 = 4.7mF.The resistance seen by the source Vs is

A. 258
B. 1258
C. 93 k
D.
Answer» C. 93 k
Discussion
119.

If the power spectral density of stationary random process is a sine-squared function of frequency, the shape of its autocorrelation is

A. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/6-02-12-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/6-02-12-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/6-02-12-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/6-02-12-4.png">
Answer» C. <img src="/_files/images/electronics-and-communication-engineering/exam-question-papers/6-02-12-3.png">
Discussion
120.

Consider the amplitude modulated (AM) signal Ac cos ct + 2 cos mt cos ct For demodulating the signal using envelope detector, the minimum value of Ac should be

A. 2
B. 1
C. 0.5
D. 0
Answer» B. 1
Discussion
121.

The normal operation of JFET is

A. constant voltage region
B. constant current region
C. both constant voltage and constant current regions
D. either constant voltage or constant current region
Answer» C. both constant voltage and constant current regions
Discussion
122.

What is the propagation constant for air filled wave guide with dimensions a = 1.59" and b = 0.795" at 4.95 GHz?

A. 0.6698
B. 0.7698
C. 0.503
D. 0.6598
Answer» B. 0.7698
Discussion
123.

Which of the following is true as regards photo emission?

A. Velocity of emitted electrons is dependent on light intensity
B. Rate of photo emission is inversely proportional to light intensity
C. Maximum velocity of electron increases with decreasing wave length
D. Both holes and electrons are produced
Answer» D. Both holes and electrons are produced
Discussion
124.

Calculate the stability factor and change in IC from 25 C to 100 C for, = 50, RB/ RE = 250, IC0 = 19.9 nA for emitter bias configuration.

A. 42.53, 0.85 A
B. 40.91, 0.58 A
C. 40.91, 0.58 A
D. 41.10, 0.39 A
Answer» B. 40.91, 0.58 A
Discussion
125.

The power dissipation in a transistor is the product of

A. emitter current and emitter to base voltage
B. emitter current and collector to emitter voltage
C. collector current and collector to emitter voltage
D. none of the above
Answer» D. none of the above
Discussion
126.

The minority carrier life time and diffusion constant in a semiconductor material are respectively 100 microsecond and 100 cm2/sec. The diffusion length is

A. 0.1 cm
B. 0.01 cm
C. 0.0141 cm
D. 1 cm
Answer» B. 0.01 cm
Discussion
127.

A periodic voltage has following value for equal time intervals changing suddenly from one value to next... 0, 5, 10, 20, 50, 60, 50, 20, 10, 5, 0, -5, -10 etc. Then rms value of the waveform is

A. 31 V
B. 32 V
C. insufficient data
D. none of these
Answer» B. 32 V
Discussion
128.

Work function of oxide coated cathode is much lower than that of tungsten cathode.

A. True
B. False
Answer» B. False
Discussion
129.

The word enhancement mode is associated with

A. tunnel diode
B. MOSFET
C. JFET
D. photo diode
Answer» C. JFET
Discussion
130.

Secondary emission is always decremental.

A. True
B. False
Answer» C.
Discussion
131.

In a degenerate n type semiconductor material, the Fermi level,

A. is in valence band
B. is in conduction band
C. is at the centre in between valence and conduction bands
D. is very near valence band
Answer» C. is at the centre in between valence and conduction bands
Discussion
132.

The types of carriers in a semiconductor are

A. 1
B. 2
C. 3
D. 4
Answer» C. 3
Discussion
133.

A potential of 7 V is applied to a silicon diode. A resistance of 1 K ohm is also in series with the diode. The current is

A. 7 mA
B. 6.3 mA
C. 0.7 mA
D. 0
Answer» C. 0.7 mA
Discussion
134.

In which region of a CE bipolar transistor is collector current almost constant?

A. Saturation region
B. Active region
C. Breakdown region
D. Both saturation and active region
Answer» C. Breakdown region
Discussion
135.

Assertion (A): The reverse saturation current in a semiconductor diode is 4nA at 20 C and 32 nA at 50 C. Reason (R): The reverse saturation current in a semiconductor diode doubles for every 10 C rise in temperature.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true
Answer» B. Both A and R are true but R is not a correct explanation of A
Discussion
136.

A zener diode is used in

A. voltage regulator circuit
B. amplifier circuits
C. both voltage regulator and amplifier circuit
D. none of the above
Answer» B. amplifier circuits
Discussion
137.

A particular green LED emits light of wavelength 5490, , the energy bandgap of the semiconductor material used there is .. h = 6.6 x 10-34 J sec.

A. 2.26 eV
B. 1.98 eV
C. 1.17 eV
D. 0.74 eV
Answer» B. 1.98 eV
Discussion
138.

Recombination produces new electron-hole pairs

A. True
B. False
Answer» C.
Discussion
139.

An amplifier without feedback has a voltage gain of 50, input resistance of 1 k&amp;ohm; and output resistance of 2.5 k&amp;ohm;. The input resistance of the current shunt -ve feedback amplifier using the above amplifier with a feedback factor of 0.2 is

A. 1/11 k&ohm;
B. 1/5 k&ohm;
C. 5 kW
D. 11 kW
Answer» B. 1/5 k&ohm;
Discussion
140.

Assertion (A): When a high reverse voltage is applied to a p-n junction the diode breaks down. Reason (R): High reverse voltage causes Avalanche effect.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. A is false but R is true
Answer» B. Both A and R are true but R is not a correct explanation of A
Discussion
141.

An LED has a rating of 2 V and 10 mA. It is used along with 6V battery. The range of series resistance is

A. 0 to 200 &ohm;
B. 200 - 400 &ohm;
C. 200 &ohm; and above
D. 400 &ohm; and above
Answer» E.
Discussion
142.

The number of doped regions in PIN diode is

A. 1
B. 2
C. 3
D. 1 or 2
Answer» C. 3
Discussion
143.

At very high temperatures the extrinsic semi conductors become intrinsic because

A. drive in diffusion of dopants and carriers
B. band to band transition dominants over impurity ionization
C. impurity ionization dominants over band to band transition
D. band to band transition is balanced by impurity ionization
Answer» C. impurity ionization dominants over band to band transition
Discussion
144.

The displacement flux density at a point on the surface of a perfect conductor is = 2(ax - 3 az)c/m2 pointing away from the surface. The charge density at that point c/m2 will be

A. 2
B. - 2
C. 4
D. - 4
Answer» D. - 4
Discussion
145.

When a voltage is applied to a semiconductor crystal then the free electrons will flow.

A. towards positive terminal
B. towards negative terminal
C. either towards positive terminal or negative terminal
D. towards positive terminal for 1 s and towards negative terminal for next 1 s
Answer» B. towards negative terminal
Discussion
146.

In a bipolar transistor the barrier potential

A. 0
B. a total of 0.7 V
C. 0.7 V across each depletion layer
D. 0.35 V
Answer» D. 0.35 V
Discussion
147.

A silicon (PN) junction at a temperature of 20 C has a reverse saturation current of 10 pico Ampere. The reverse saturation current at 40 C for the same bias is approximately.

A. 30 pA
B. 40 pA
C. 50 pA
D. 60 pA
Answer» C. 50 pA
Discussion
148.

Find the noise factor for an antenna at 27 C with equivalent noise temperature 30 K

A. 20
B. 100
C. 300
D. 1.1
Answer» E.
Discussion
149.

Characteristic impedance of a transmission line is 50 &amp;ohm;. Input impedance of the open circuited line. Zoc = 100 + J150 &amp;ohm;. When transmission line is short circuited, then value of the input impedance will be

A. 50 &ohm;
B. 100 + J150 &ohm;
C. 7.69 + J11.54&ohm;
D. 7.69 - J11.54 &ohm;
Answer» E.
Discussion
150.

What is the characteristic impedance at 10 MHz?

A. 547.7 &ohm;
B. 54.7 &ohm;
C. 5.47 &ohm;
D. .547 &ohm;
Answer» B. 54.7 &ohm;
Discussion