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MCQOPTIONS
This section includes 902 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.
| 501. |
Consider Pole zero diagram as shown, If two Poles are moved in opposite direction towards ω = p/2 and -p/2, the filter will be |
| A. | change to high pass filter |
| B. | change to Band Pass filter |
| C. | remains same |
| D. | change to LPF |
| Answer» D. change to LPF | |
| 502. |
The range of value "a" for which system will be stable. If impulse response of DT system is = an ‚à™[n] |
| A. | a > 1 |
| B. | a < 1 |
| C. | 1 < a < ‚àû |
| D. | #NAME? |
| Answer» E. | |
| 503. |
If f(- t) = f(t), the function f(t) has only cosine terms. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 504. |
Fourier transform o the function f(t) = 1 is |
| A. | 2p δ (ω) |
| B. | p δ (ω) |
| C. | δ(ω)/2p |
| D. | δ(ω)/p |
| Answer» B. p Œ¥ (œâ) | |
| 505. |
A complex wave is 5 + 5 sin ωt. Its rms value is |
| A. | 7.07 V |
| B. | 5 V |
| C. | 10 V |
| D. | 6.12 V |
| Answer» E. | |
| 506. |
A function will have only sine terms if |
| A. | f(t) = - f(t) |
| B. | f(-t) = f(t) |
| C. | f(-t) = -f(t) |
| D. | none of the above |
| Answer» D. none of the above | |
| 507. |
If Fn represents Fourier series coefficient of f(t), then Fourier series coefficient of f(t + t) = |
| A. | Fne -jω0t |
| B. | Fne jω0t |
| C. | Fne jnω0t |
| D. | Fne -jnω0t |
| Answer» D. Fne -jnœâ0t | |
| 508. |
The minor Mij of an n x n matrix is the determinant of (n - 1) x (n - 1) matrix formed by deleting the ith row and j the column of n x n matrix. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 509. |
A rectangular pulse train s(t) is shown in figure is convolved with the signal cos2(4p x 103t). The convolved signal will be a |
| A. | DC |
| B. | 12 kHZ sinusoidal |
| C. | 8 kHZ sinusoidal |
| D. | 14 kHZ sinusoidal |
| Answer» E. | |
| 510. |
A stationary process has |
| A. | zero variance |
| B. | ensemble average equal to time average |
| Answer» B. ensemble average equal to time average | |
| 511. |
The function shown in the figure |
| A. | unit step function |
| B. | none of the above |
| Answer» C. | |
| 512. |
Choose the function f(t), - ‚àû < t < + ‚àû, for which a Fourier series cannot be defined |
| A. | 3 sin (25t) |
| B. | 4 cos (20t + 3) + 2 sin (10t) |
| C. | exp - | t | sin 25 t |
| D. | 1 |
| Answer» D. 1 | |
| 513. |
The DTFT of x(n) = δ(n) will be |
| A. | 1 |
| B. | 0 |
| C. | ‚àû |
| D. | not defined |
| Answer» B. 0 | |
| 514. |
A voltage v(t) which is a gaussian ergodic random process witha mean of zero and a varance of 4 volt2 is measured by a meter which first square and then reads its dc component. The reading will be |
| A. | 0 |
| B. | 4 |
| C. | 16 |
| D. | 2 |
| Answer» C. 16 | |
| 515. |
If a signal g(t) has energy E, then the energy of the signal g(2t) is equal to ... |
| A. | E/2 |
| B. | E/4 |
| C. | E |
| D. | 2E |
| Answer» B. E/4 | |
| 516. |
Assertion (A): If Reason (R): Displacement in time domain by T becomes multiplication by e-st in s domain. |
| A. | A is true, R is false |
| B. | A is false, R is true |
| Answer» C. | |
| 517. |
In the given figure 15.6 shows a series, R - C circuit fed by a current source i(t). There is an initial voltage v0. across the capacitor. The system |
| A. | is linear |
| B. | is non linear |
| C. | may be linear or non linear |
| D. | is linear only if v0 is zero |
| Answer» E. | |
| 518. |
For the single rectangular pulse of the given figureF(jω) = [Ad sin (ωd/2)]/(ωd/2). |
| A. | 1 |
| B. | |
| Answer» B. | |
| 519. |
The impulse response h[n] of a linear time invariant system is given asIf the input to the above system is the sequence ejpn/4, then the output is |
| A. | 42 ejpn/4 |
| B. | 42 e- jpn/4 |
| C. | 4epn/4 |
| D. | -4epn/4 |
| Answer» B. 42 e- jpn/4 | |
| 520. |
Assertion (A): The wave shown in the given figure does not contain the dc component and even harmonicsReason (R): If f(- t) = f(t) the wave has only cosine terms. |
| 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 true, R is false |
| D. | A is false, R is true |
| Answer» C. A is true, R is false | |
| 521. |
Which one of following is correct condition to check the stability of sysytem in terms of impulse response? |
| A. | Σx(n) = 0 |
| B. | Σx(n) = ∞ |
| Answer» B. Œ£x(n) = ‚àû | |
| 522. |
Which one of the following rules determines the mapping of s-plane to z-plane? |
| A. | Right half of the s-plane maps into outside of the unit circle in z-plane |
| B. | Left half of the s-plane maps into outside of the unit circle. |
| C. | Imaginary axis in s-plane maps in to the circumference of the unit circle. |
| D. | All of the above |
| Answer» E. | |
| 523. |
The following table gives some time functions and the Laplace transformsOf these correctly matched pairs are |
| A. | 3 and 4 |
| B. | 1 and 2 |
| Answer» B. 1 and 2 | |
| 524. |
If autocorrelation sequence is Rc(n) = then what will be energy of sequence? |
| A. | 2 |
| B. | 24 |
| C. | 3 |
| D. | 288 |
| Answer» D. 288 | |
| 525. |
Principle of superposition is applicable to |
| A. | linear systems only |
| B. | nonlinear systems only |
| C. | both linear and non linear system |
| D. | linear systems and some nonlinear systems |
| Answer» B. nonlinear systems only | |
| 526. |
An ac sinusoidal wave has an rms value of 10 V. The peak to peak value is |
| A. | 10 V |
| B. | 0 V |
| C. | 14.14 V |
| D. | 28.28 V |
| Answer» E. | |
| 527. |
ROC of sequence x[n] = (3)n ‚à™[n] + (4)n ‚à™[- n - 1] |
| A. | |z| > 4 |
| B. | 3 < |z| < 4 |
| C. | |z| < 4 |
| D. | |z| > 3 |
| Answer» C. |z| < 4 | |
| 528. |
e-3t is a |
| A. | energy signal |
| B. | power signal |
| C. | Both (a) and (b) |
| D. | none |
| Answer» E. | |
| 529. |
The term 'energy spectral density' is associated with |
| A. | both perodic and non -perodic waveform |
| B. | none of the above |
| C. | 1 |
| D. | |
| Answer» C. 1 | |
| 530. |
Which one of the following is the correct statement of the system characterized by the equation y(t) = ax(t) + b? |
| A. | linear for any value of b |
| B. | linear if b > 0 |
| C. | linear if b < 0 |
| D. | non-linear |
| Answer» E. | |
| 531. |
If average correlation between v1(t) and v2(t) is R12(t) and average correlation between v2(t) and v1(t) is R21(t) then |
| A. | R12(t) = - R21(t) |
| B. | none of these |
| C. | all statistical properties independent of time |
| D. | all statistical properties dependent of time |
| Answer» C. all statistical properties independent of time | |
| 532. |
In the representation f(t) = the set of complex coefficient Fn is the frequency spectrum of f(t) |
| A. | a ramp of slope k |
| B. | a ramp of slope 1/k |
| C. | k δ(t) |
| Answer» B. a ramp of slope 1/k | |
| 533. |
Magnitude Plot of a Composite signal x(t) = e2jt + e3jt is |
| A. | half wave rectified sinusoidal |
| B. | full wave rectified sinusoidal |
| C. | exponentially increasing sinusoidal |
| D. | exponentially decreasing sinusoidal |
| Answer» C. exponentially increasing sinusoidal | |
| 534. |
The Fourier transform of f(t) = cos ω0t is |
| A. | p[δω0 - δ(- ω0)] |
| B. | p[δ(ω - ω0) - δ(ω + ω0)] |
| C. | impulse function |
| D. | signum function |
| Answer» C. impulse function | |
| 535. |
The signumm function written as [sgn(t)] is defined as |
| A. | sgn(t) = - 1 for t < 0, = 0 for t = 0 and = 1 for t > 0 |
| B. | sgn(t) = 1 for t < 0, = 0 for t = 0 and = - 1 for t > 0 |
| C. | sgn(t) = 0 for t < 0, = 1 for t = 0 and = 0 for t > 0 |
| D. | sgn(t) = 0 for t < 0, = 1 for t3 0 |
| Answer» B. sgn(t) = 1 for t < 0, = 0 for t = 0 and = - 1 for t > 0 | |
| 536. |
If Laplace transform of f(t) is F(s), then = |
| A. | s F(s) - f(0-) |
| B. | |
| Answer» B. | |
| 537. |
An ac network has a power factor of 0.8 leading if the applied wave is of fundamental frequency. If the applied wave contains third and fifth harmonics, the overall power factor will be |
| A. | 0.8 leading |
| B. | less than 0.8 leading |
| C. | more than 0.8 leading |
| D. | 0.8 leading or more |
| Answer» D. 0.8 leading or more | |
| 538. |
The function f(t) = E[u(t - a) - u(t - b)] is |
| A. | an exponential function originating at t = a |
| B. | a pulse function originating at t = a and duration (b - a) |
| C. | 1 |
| D. | |
| Answer» E. | |
| 539. |
Assertion (A): The modified ramp function of the given figure can be represented s sum of two ramp functions of the given figure Reason (R): If f(t) = t, F(s) = 1 |
| 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 true, R is false |
| D. | A is false, R is true |
| Answer» D. A is false, R is true | |
| 540. |
The unit step response of a system is (1 - eat) u(t). Then its impulse response is |
| A. | e- at u(t) |
| B. | ae- at u(t) |
| C. | |
| Answer» C. | |
| 541. |
Half wave sysmmetry means f(t) = - f(t ± T/2). |
| A. | 0 |
| B. | 1 |
| C. | ‚àû |
| D. | 2 |
| Answer» B. 1 | |
| 542. |
Fourier transform pair are |
| A. | autocorrelation and power spectral density |
| B. | autocorrelation and convoloution |
| C. | convolution and power spectral density |
| D. | autocorrelation and energy |
| Answer» B. autocorrelation and convoloution | |
| 543. |
In Laplace transforms s = σ + jω. Which of the following represents true natue of s. Select your answer using the given codes σ has a damping effectσ is responsible for convergence of integral f(t)e-st dtσ has a value less than zero Codes: |
| A. | 2 and 3 |
| B. | 1 and 3 |
| C. | Both A and R are correct and R is correct explanation of A |
| D. | Both A and R are correct but R is not correct explanation of A |
| Answer» C. Both A and R are correct and R is correct explanation of A | |
| 544. |
If sequence y(n) = x(-n) then it is |
| A. | Causal |
| B. | Non-Causal |
| C. | Depends on x(-n) |
| D. | None |
| Answer» D. None | |
| 545. |
The n state variables can be considered as n components of a state vector. |
| A. | 1 |
| B. | |
| C. | external interference |
| D. | random variations |
| Answer» B. | |
| 546. |
A unit step function is used to represent the closing a switch in a constant voltage system. |
| A. | 0.0314 cos 314 t + 0.0157 cos 1570 t |
| B. | 0.0314 sin 314 t + 0.0157 sin 1570 t |
| C. | 0.0314 cos 314 t + 0.0314 cos 1570 t |
| D. | 0.0157 cos 314 t + 0.0157 cos 1570 t |
| Answer» B. 0.0314 sin 314 t + 0.0157 sin 1570 t | |
| 547. |
If xk is one sided to the right |
| A. | an ‚à™(n - 2) |
| B. | an-2 ‚à™(n) |
| C. | an+2 ‚à™(n) |
| D. | an ‚à™(n + 2) |
| Answer» B. an-2 ‚à™(n) | |
| 548. |
What about causality of the system transfer function of a discrete time system |
| A. | uncasual |
| B. | casual |
| C. | casual and some specific point |
| D. | Both b and c |
| Answer» C. casual and some specific point | |
| 549. |
The z transform of sequence x[n] = {2, 4, 3, 2} |
| A. | 2z-1 + 4z-2 + 3 + 2z+1 |
| B. | 2z-1 + 3 + 4z+1 + + 2z+2 |
| C. | 2z+1 + 3z-1 + 4z-2 + 2z-3 |
| D. | 3 + 2z-1 + 4z-2 + 2z-1 |
| Answer» E. | |
| 550. |
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. | unity |
| B. | < 1 |
| C. | 3.2 + 0.171 w |
| D. | 2.28 + 0.1879 w |
| Answer» C. 3.2 + 0.171 w | |