Explore topic-wise MCQs in Testing Subject.

This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.

1.

A linear discrete time system has the char. equation z3 - 0.81z = 0, the system is

A. stable
B. marginally stable
C. unstable
D. stability cannot be assessed from the given information
Answer» B. marginally stable
Discussion
2.

which is the Laplace transform of x(t) = -e2t (t) t (t)?

A. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-380-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-380-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-380-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-380-4.png">
Answer» C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-380-3.png">
Discussion
3.

Highest value of Autocorrelation of a function 100 cos 50 pt is

A. 50
B. 100
C. zero
D. 100/
E. <span class="symbol">p</span>
Answer» C. zero
Discussion
4.

Short circuit is the dual of open circuit.

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

Energy density function is always

A. even
B. odd
C. neither even nor odd
D. both (a) and (b)
Answer» B. odd
Discussion
6.

Which one of the following is the correct statement? The region of convergence of z transform of x[n] consists of the values of z for which x[n] r-n is

A. absolutely integrable
B. absolutely summable
C. unity
D. < 1
Answer» C. unity
Discussion
7.

Laplace transforn of sin ( t + a) is

A. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/12-160-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/12-160-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/12-160-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/12-160-4.png">
Answer» C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/12-160-3.png">
Discussion
8.

A system with input x[n] and output y[n] is given as y[n] = (sin 5/6 pn) x(n) The system is

A. linear, stable and invertible
B. non-linear, stable and non-invertible
C. linear stable, non invertible
D. linear, unstable, invertible
Answer» D. linear, unstable, invertible
Discussion
9.

The impulse response h[n] of a linear time invariant system is given by h[n] = [n + 3 ] + [n - 2] -2 [n -7]. The above system is

A. stable but non-casual
B. stable and casual
C. casual but unstable
D. unstable and not casual
Answer» B. stable and casual
Discussion
10.

If v(t) = 0 for t &lt; 0 and e-at for t 0 V(j ) = 1/(a + j ).

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

The term 'energy spectral density' is associated with

A. periodic waveform
B. non-periodic waveform
C. both perodic and non -perodic waveform
D. none of the above
Answer» C. both perodic and non -perodic waveform
Discussion
12.

If f(t) = 1, F(j ) = 2p ( ).

A. True
B. False
Answer» B. False
Discussion
13.

The state equations are in the form

A. X = AX + BW
B. X = AX + Bu
C. X = AX + Bx
D. either (a) or (b)
Answer» B. X = AX + Bu
Discussion
14.

Following is a reason of distortion in communication system

A. external interference
B. random variations
C. insufficient Channel Bandwidth
D. all
Answer» E.
Discussion
15.

The n state variables can be considered as n components of a state vector.

A. True
B. False
Answer» B. False
Discussion
16.

The Laplace transform of sin t is

A. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/05-28-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/05-28-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/05-28-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/05-28-4.png">
Answer» B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/05-28-2.png">
Discussion
17.

Fourier series is applicable for

A. periodic
B. finite duration
C. non periodic
D. a and b
Answer» E.
Discussion
18.

Fourier transform of the unit step function (i.e., u(t) = 1 for t 0 and u(t) = 0 for t &lt; 0) is

A. <span class="symbol">p</span>
B. ( )
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/11-142-2.png">
D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/11-142-3.png">
E. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/11-142-4.png">
Answer» D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/11-142-3.png">
Discussion
19.

The F.T. X(f) of the periodic delta functions.

A. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/23-395-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/23-395-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/23-395-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/23-395-4.png">
Answer» D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/23-395-4.png">
Discussion
20.

The dirac delta function (t) is defined as

A. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-372-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-372-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-372-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-372-4.png">
Answer» E.
Discussion
21.

For the single rectangular pulse of the given figureF(j ) = [Ad sin ( d/2)]/( d/2).

A. True
B. False
Answer» B. False
Discussion
22.

Out of the three transforms viz. Z-transform, Laplace transform and Fourier transform

A. all three are used in continuous time domain
B. all three are used in both continuous time domain and discrete time domain
C. Z transform is used in continuous time domain while Laplace and Fourier transforms are used in discrete time domain
D. Z transform is used is discrete time domain while Laplace and Fourier transforms are used in continuous time domain
Answer» E.
Discussion
23.

The inverse z-transform of X(z) is

A. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-381-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-381-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-381-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-381-4.png">
Answer» B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/22-381-2.png">
Discussion
24.

In the representation f(t) = the set of complex coefficient Fn is the frequency spectrum of f(t)

A. True
B. False
Answer» B. False
Discussion
25.

A number of impulses spaced fron one another form an impulse train.

A. True
B. False
Answer» B. False
Discussion
26.

In a complex wave, the negative half of the wave is a reproduction of the positive half wave. Then

A. the wave contains only fundamental and third harmonic
B. the wave does not contain even harmonics
C. the wave does not contain odd harmonics
D. the wave does not contain triple harmonics
Answer» C. the wave does not contain odd harmonics
Discussion
27.

consider the following as regards cumulative disribution function F(x)0 F(x) 1F(- ) = 0F( ) = 1F(x1) F(x2) If x1 &lt; x2 Out of above which are correct?

A. 1 and 2 only
B. 1, 2 and 3 only
C. 1, 2, 3 and 4
D. 2 and 4
Answer» D. 2 and 4
Discussion
28.

If and k &gt; 0 X(z) = - In (1 - z-1) with 1 &lt; |z|

A. True
B. False
Answer» B. False
Discussion
29.

The impulse response of the DT - LTI system is given below Check whether the system is StableCasualDynamic.

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

The units of F(j ) are volt-seconds.

A. True
B. False
Answer» B. False
Discussion
31.

If f (t) is an even function, then in th form

A. True
B. False
Answer» B. False
Discussion
32.

unit step is a

A. energy signal
B. power signal
C. neither energy nor power signal
D. none
Answer» C. neither energy nor power signal
Discussion
33.

The eign values of n x n matrix A are the root of the characteristic equation 1 I - AI = 0

A. True
B. False
Answer» B. False
Discussion
34.

(SI - A)-1 = adj(sI - A)/det (sI - A)

A. True
B. False
Answer» B. False
Discussion
35.

A pulse function can be represented as difference of two equal step functions.

A. True
B. False
Answer» B. False
Discussion
36.

If f(t) is an even function, F(j ) =

A. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-74-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-74-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-73-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-73-4.png">
Answer» B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-74-2.png">
Discussion
37.

An experiment is repeated N times. One event A occurs NA times. Then

A. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/15-216-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/15-216-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/15-216-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/15-216-4.png">
Answer» C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/15-216-3.png">
Discussion
38.

If I(s) = , fnal value of i(t) is

A. 0
B. 2.5
C. 12.5
D.
Answer» D.
Discussion
39.

Choose correct option

A. var (X + Y) = Var (X) + Var (Y)
B. var (X - Y) = Var (X) + Var (Y)
C. var (X + Y) = Var (X) x Var (Y)
D. Both (a) and (b)
Answer» E.
Discussion
40.

If v(t) is a time varying voltage, is

A. initial current
B. initial voltage
C. initial charge
D. initial flux leakages
Answer» E.
Discussion
41.

An ac network has a power factor of 0.8 lagging for fundamental frequency. If the applied voltage contains thrid and fifth harmonics, the overall power factor will be

A. more than 0.8 lagging
B. 0.8 lagging
C. less than 0.8 lagging
D. 0.8 lagging or less
Answer» D. 0.8 lagging or less
Discussion
42.

If otherwise find E(X)

A. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/17-272-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/17-272-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/17-272-3.png">
D. 0
Answer» B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/17-272-2.png">
Discussion
43.

Which of the following is the correct Laplace transform of the signal shown in the given figure

A. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/10-136-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/10-136-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/10-136-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/10-136-4.png">
Answer» C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/10-136-3.png">
Discussion
44.

Which of the following can be impulse response of a casual system?

A. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/21-363-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/21-363-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/21-363-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/21-363-4.png">
Answer» C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/21-363-3.png">
Discussion
45.

A voltage V(t) which is a Gaussian ergodic random process with a mean of zero and a variance of 4 volt2 is measured by a true rms meter. The reading will be

A. 0
B. 4
C. 2
D. 16
Answer» D. 16
Discussion
46.

If f(t) is in volts, then F(j ) is in

A. volts
B. volt seconds
C. volts/sec
D. volt-sec
E. <sup>2</sup>
Answer» C. volts/sec
Discussion
47.

The Nyquist sampling interval, for the signal sinc (700t) + sinc (500t) is

A. 1/350 sec
B. <span class="symbol">p</span>
C. /350 sec
D. 1/700 sec
E. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/20-345-4.png">
Answer» D. 1/700 sec
Discussion
48.

The integral of a unit impulse is

A. a unit step function
B. a ramp function of slope 1
C. a pulse function of magnitude 1
D. none of the above
Answer» B. a ramp function of slope 1
Discussion
49.

State variable formulation is very suitable for computer solution.

A. True
B. False
Answer» B. False
Discussion
50.

A wave f(t) has half wave symmetry and time period equal to T. Then

A. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/06-62-1.png">
B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/06-62-2.png">
C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/06-62-3.png">
D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/06-62-4.png">
Answer» E.
Discussion