Explore topic-wise MCQs in Electronics & Communication Engineering.

This section includes 519 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics & Communication Engineering knowledge and support exam preparation. Choose a topic below to get started.

1.

N circles for a = a1, and a = a1 ± 180° n (where n = 1, 2, 3, ....) are the same.

A. True
B. False
Answer» B. False
Discussion
2.

Nichol's chart is symmetric about - 180° axis.

A. True
B. False
Answer» B. False
Discussion
3.

At low frequencies the factor e-jωT and behave simple.

A. True
B. False
Answer» B. False
Discussion
4.

For type 0 system the starting point (i.e. ω = 0) of polar plot is finite and is on positive real axis.

A. True
B. False
Answer» B. False
Discussion
5.

For as ω approaches infinity, the magnitude approaches zero and phase angle approaches - 90°.

A. True
B. False
Answer» B. False
Discussion
6.

The phase angle curve of G(jω) H(jω) is drawn by adding the phase angles of individual factors.

A. True
B. False
Answer» B. False
Discussion
7.

At corner frequency the phase angle of factor is - 45°

A. True
B. False
Answer» B. False
Discussion
8.

The phase angle of is constant and equal to - 90° for all values of ω

A. True
B. False
Answer» B. False
Discussion
9.

The log magnitude curve of factor jω is a straight line having a slope of 20 dB/decade.

A. True
B. False
Answer» B. False
Discussion
10.

Transfer functions of even complicated components can be found by frequency response tests.

A. True
B. False
Answer» B. False
Discussion
11.

Assertion (A): For a given system only one of the static error constants is finite and significant.Reason (R): If finite static error constant is large, the loop gain becomes smaller as ω approaches zero.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» D. R is correct but A is wrong
Discussion
12.

Assertion (A): The steady state response, of a stable, linear, time invariant system, to sinusoidal input depends on initial conditions. Reason (R): Frequency response, in steady state, is obtained by replacing s in the transfer function by jω

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» E.
Discussion
13.

Assertion (A): F(s) is valid throughout s plane except at poles of F(s).Reason (R): £[f1(t) + f2(t)] = £[f1(t)] + £[f2(t)]

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» C. A is correct but R is wrong
Discussion
14.

Assertion (A): For an underdamped system with damping ratio ξ, the maximum overshoot is e-ξp/(1-ξ2)0.5Reason (R): Peak time of a second order under damped system = p/ωd where ωd is frequency of damped oscillations.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» C. A is correct but R is wrong
Discussion
15.

Assertion (A): An on off controller gives rise to oscillation of the output between two limits.Reason (R): Location of a pair of poles on jω axis gives rise to self sustained oscillations in the output.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» C. A is correct but R is wrong
Discussion
16.

Assertion (A): The closeness of G(jω) locus to (- 1 + j0) point can be used as a measured of margin of stability.Reason (R): When the G(jω) locus comes close to encircling (- 1 + j0) point the system becomes oscillatory.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» B. Both A and R are correct but R is not correct explanation of A
Discussion
17.

Assertion (A): If minimum phase system has a gain margin of 8 dB and phase margin of 21°, the system is stable.Reason (R): For a minimum phase system both GM and PM must be positive for the system to be stable.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» B. Both A and R are correct but R is not correct explanation of A
Discussion
18.

Assertion (A): A. For a unity feedback system, with , the settling time of step response is constant for all values of K ≥ 1Reason (R): The real part of the roots for all values of K ≥ 1 are negative.

A. Both A and R are correct and R is correct explanation of A
B. Both A and R are correct but R is not correct explanation of A
C. A is correct but R is wrong
D. R is correct but A is wrong
Answer» B. Both A and R are correct but R is not correct explanation of A
Discussion
19.

The given figure shows log magnitude versus ω plots of a system for different values of gain. For this system

A. curve 1 shows highest gain margin and curve 2 shows poorest gain margin
B. gain margins shown by the three curves are equal
C. curve 1 shows poorest gain margin and curve 3 shows highest gain margin
D. curve 3 shows poorest gain margin while curve 1 shows highest gain margin
Answer» D. curve 3 shows poorest gain margin while curve 1 shows highest gain margin
Discussion
20.

The Nyquist plot in the given figure is for G(s) H(s) =

A. [A].
B. [B].
C. [C].
D. [D].
Answer» D. [D].
Discussion
21.

The slope of log-magnitude asymptote changes by - 40 dB/ decade at a frequency ω1. This means that

A. a double pole is present
B. a pair of complex conjugate poles is present
C. either a double pole or a pair of complex conjugate poles is present
D. a pole or zero at origin is present
Answer» D. a pole or zero at origin is present
Discussion
22.

For G(jω) =

A. magnitude is 1 at all frequencies and phase angle varies from 0 to - 180° as ω varies from 0 to ∞
B. magnitude is T at all frequencies and phase angle 0
C. magnitude is (1 + ω2T2)0.5 and phase angle varies from0 to 0 - 180° as ω varies from 0 to ∞
D. none of the above
Answer» B. magnitude is T at all frequencies and phase angle 0
Discussion
23.

For the factor (1 + 0.5 jω) the corner frequency is

A. 1 rad/sec
B. 0.5 rad/sec
C. 2 rad/sec
D. 0.25 rad/sec
Answer» D. 0.25 rad/sec
Discussion
24.

For Bode plot of (1 + jωT) has

A. slope of 20 dB/decade and phase angle + tan-1 (ωT)
B. slope of - 20 dB/decade and phase angle + tan-1 (ωT)
C. slope of 20 dB/decade and phase angle - tan-1 (ωT)
D. slope of - 40 dB/decade and phase angle - tan-1(ωT)
Answer» B. slope of - 20 dB/decade and phase angle + tan-1 (ωT)
Discussion
25.

The polar plot in the given figure is for G(jω) =

A. [A].
B. [B].
C. [C].
D. [D].
Answer» D. [D].
Discussion
26.

For the plot in the given figure, G(jω) =

A. [A].
B. [B].
C. [C].
D. [D].
Answer» E.
Discussion
27.

Consider the following statements about polar plots Addition of a non-zero pole to a transfer function results in further rotation of polar plot through an angle of - 90° as ω → ∞Addition of a pole at the origin to a transfer function rotates the polar plot at zero and infinite frequencies by a further angle of - 90° Of the above statements:

A. Both are correct
B. Both are wrong
C. 1 is correct and 2 is wrong
D. 2 is correct and 1 is wrong
Answer» B. Both are wrong
Discussion
28.

The polar plot of the given figure can be for G(jω) =

A. [A].
B. [B].
C. [C].
D. [D].
Answer» C. [C].
Discussion
29.

Consider the following statements: If any root of characteristic equation has a positive real part the impulse response is unbounded and system is unstable.If all the roots of a characteristic equation have negative real parts, the impulse response decays to zero.If one or more non-repeated roots of characteristic equation are on jω axis impulse response is bounded but the system is unstable. Which of the above equations are correct?

A. 1, 2 and 3
B. 1 and 2 only
C. 1 and 3 only
D. 2 and 3 only
Answer» B. 1 and 2 only
Discussion
30.

If feedback factor is β the overall gain of a closed loop system is approximately equal to

A. [A].
B. [B].
C. β
D. β
Answer» C. β
Discussion
31.

For a second order system ωn is natural frequency, ωd is frequency of damped oscillations and ζ is damping factor. Then

A. ωd = ωn ξ
B. ωd = ωn (1 - ξ)2
C. ωd = ωn (1 - ξ)0.5
D. ωd = ωn (1 - ξ2)0.5
Answer» E.
Discussion
32.

For a second order system damping factor is 0.1. If ωd is frequency of damped oscillations and ωn is natural frequency, then

A. ωd ≈ ωn
B. [B].
C. ωn ≈ ωn
D. ωd ≈ (ωn)2
Answer» B. [B].
Discussion
33.

For a second order system with 0 < ξ < 1, the angle which poles make with negative real axis is

A. sin-1 ξ
B. cos-1 ξ
C. tan-1 ξ
D. cot-1 ξ
Answer» C. tan-1 ξ
Discussion
34.

In the given figure, R2 >> R1. Then

A. [A].
B. [B].
C. [C].
D. [D].
Answer» B. [B].
Discussion
35.

If ΔP is pressure difference, A is area of each flat surface, K is stiffness and Δx is displacement of movable surface from reference of bellows, then

A. [A].
B. [B].
C. [C].
D. [D].
Answer» D. [D].
Discussion
36.

For the given figure,

A. [A].
B. [B].
C. [C].
D. [D].
Answer» C. [C].
Discussion
37.

In the given figure

A. [A].
B. [B].
C. [C].
D. [D].
Answer» B. [B].
Discussion
38.

In the given figure, C(s) =

A. [A].
B. [B].
C. [C].
D. [D].
Answer» C. [C].
Discussion
39.

In an armature controlled dc motor let J be equivalent moment of inertia of motor and load, f0 be equivalent viscous friction coefficient of motor and load and θ be angular displacement of motor shaft. Then torque equation is

A. [A].
B. [B].
C. [C].
D. [D].
Answer» B. [B].
Discussion
40.

The radius of constant N circle for N = 1 is

A. 2
B. 2
C. 1
D. [D].
Answer» E.
Discussion
41.

For the feedback system with closed loop transfer function the settling time for 2% tolerance

A. [A].
B. [B].
C. [C].
D. 4ξωn
Answer» D. 4ξωn
Discussion
42.

Given figure shows a magnitude Bode plot. The transfer function for this plot is

A. [A].
B. [B].
C. [C].
D. [D].
Answer» D. [D].
Discussion
43.

A phase lead network with where a < 1, gives maximum phase lead at a frequency equal to

A. [A].
B. [B].
C. [C].
D. [D].
Answer» D. [D].
Discussion
44.

For a feedback systemThen the velocity error constant Kv is given by

A. [A].
B. [B].
C. [C].
D. [D].
Answer» B. [B].
Discussion
45.

For the circuit in the given figure, V2(s)/V1(s) =

A. [A].
B. [B].
C. [C].
D. [D].
Answer» C. [C].
Discussion
46.

The phase difference (jω - p1) means

A. phasor drawn from p1 to jω
B. phasor drawn from origin to p1
C. phasor directed from origin to jω point
D. phasor directed from jω to p1
Answer» B. phasor drawn from origin to p1
Discussion
47.

An RLC series circuit hasIf poles p1 and p1* are close to jω axis, then

A. resonant frequency is high
B. Q is high
C. bandwidth is large
D. Q is low
Answer» D. Q is low
Discussion
48.

For an RLC series circuit Z(s) is of the form

A. [A].
B. [B].
C. [C].
D. [D].
Answer» E.
Discussion
49.

If the angle of departure of root locus at s = - 1 + j is

A. zero
B. 90°
C. -90°
D. -180°
Answer» E.
Discussion
50.

For the system of the given figure the transfer function is

A. [A].
B. [B].
C. [C].
D. [D].
Answer» E.
Discussion