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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.
| 351. |
If xk = 0 for k < 0 and = 2^k for k ≥ 0 X(z) = z/(z -2). |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 352. |
Consider the sequence x[n] = [- 4 - j5 1 + J2 4] |
| A. | [- 4 - J2.5 J2 4 - J2.5] |
| B. | [- J2.5 1 J2.5] |
| C. | [- J5 J2 0] |
| D. | [- x 1 4] |
| Answer» D. [- x 1 4] | |
| 353. |
If transfer function of a system is H(z) = 6 + z¯¹ + z¯², then system is |
| A. | minimun phase |
| B. | maximum phase |
| C. | mixed phase |
| D. | none |
| Answer» B. maximum phase | |
| 354. |
ROC of sequence x[n] = δ[n] is |
| A. | Not exist |
| B. | z = 0 |
| C. | Entire Plane |
| D. | Entire Plane expect z = 0, z = ∞ |
| Answer» D. Entire Plane expect z = 0, z = ∞ | |
| 355. |
If X(z) = (1 - az¯¹), and |a| < |z|, the initial value x₀ is |
| A. | 1 |
| B. | 0 |
| C. | 2 |
| D. | ∞ |
| Answer» B. 0 | |
| 356. |
A first order system will never be able to give a __________ response1. band stop2. band pass3. all 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 | |
| 357. |
As per normal distribution the probability of an error between limits a and b is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 358. |
Consider the following statements 1. If ensemble and time averages of a random process are identical, the process is ergodic.2. If ensemble and time average of a random process are not identical, the process is ergodic.3. An ergodic process is stationary.4. A stationary process is necessarily ergodic. Which of the above statements are correct? |
| A. | 1 only |
| B. | 1 and 3 only |
| C. | 1, 3 and 4 only |
| D. | 1 and 4 only |
| Answer» C. 1, 3 and 4 only | |
| 359. |
The power in the signal s(t) = 8 cos (20 π - π/2) + 4 sin (15 πt) is |
| A. | 40 |
| B. | 41 |
| C. | 42 |
| D. | 82 |
| Answer» B. 41 | |
| 360. |
If R(τ) is autocorrelation of a waveform v(t) and R(0) is autocorrelation for τ = 0, then |
| A. | R(0) > R(τ) |
| B. | R(0) ≥ R(τ) |
| C. | R(0) < R(τ) |
| D. | R(0) ≤ R(τ) |
| Answer» C. R(0) < R(τ) | |
| 361. |
If F(t) = δ(t - a), F(s)= |
| A. | 0 |
| B. | 1 |
| C. | e^(-as) |
| D. | e^(as) |
| Answer» D. e^(as) | |
| 362. |
If £ f(t) = F(jω), then |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 363. |
If Laplace transform of f(t) is F(s), then |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 364. |
If f(t) is an odd function, F(jω) = |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 365. |
If f(t) ↔ F(jω), |
| A. | F(jω) |
| B. | [F(jω)]ⁿ |
| C. | (jω)ⁿ F(jω) |
| D. | (jω) / F(jω)ⁿ |
| Answer» D. (jω) / F(jω)ⁿ | |
| 366. |
A voltage v = 5 + 50 sin ωt + 5 sin 5 ωt is applied to a pure capacitor of capacitance 1 ωF. If f/= 314 rad/sec, current is |
| A. | 1 + 0.0157 cos 314 t + 0.00785 cos 1570 t |
| B. | 0.0157 cos 314 t + 0.00785 cos 1570 t |
| C. | 0.0157 sin 314 t + 0.00785 sin 1570 t |
| D. | 0.0157 sin (314 t / + 45°) + 0.00785 sin (1570 t + 45°) |
| Answer» C. 0.0157 sin 314 t + 0.00785 sin 1570 t | |
| 367. |
Following is a reason of distortion in communication system |
| A. | external interference |
| B. | random variations |
| C. | insufficient Channel Bandwidth |
| D. | all |
| Answer» E. | |
| 368. |
Which of the following is not true for impulse function δ(t)? |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 369. |
Which one of the following digital filters does have a linear phase response? |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 370. |
The Laplace transform of impulse δ(t) is |
| A. | 1 |
| B. | 1/s |
| C. | s |
| D. | 1/s² |
| Answer» B. 1/s | |
| 371. |
Highest value of autocorrelation function 100 sin 50 πt is |
| A. | 50 |
| B. | zero |
| C. | 100 |
| D. | 100/π |
| Answer» C. 100 | |
| 372. |
The ROC of sequence x[n] = (0.8)ⁿ ∪[n] + (0.4)ⁿ ∪[n] |
| A. | |z| > 0.8 |
| B. | |z| > 0.4 |
| C. | 0.4 < |z| < 0.8 |
| D. | |z| < 0.8 |
| Answer» B. |z| > 0.4 | |
| 373. |
The discrete time system describes by y(n) = x(n²) is |
| A. | casual, Linear, time varying |
| B. | casual, non-linear, timevari |
| C. | non-casual, Linear, time invariant |
| D. | non-casual, non-linear, time variant |
| Answer» B. casual, non-linear, timevari | |
| 374. |
A voltage wave is i = 100 sin (ωt). Its average value calculated over one half cycle is |
| A. | zero |
| B. | 70.72 V |
| C. | 63.70 V |
| D. | none of the above |
| Answer» D. none of the above | |
| 375. |
For an ac sinusoidal wave, the rms value is 10 A. For the same wave delayed by 60° in each half cycle, the rms value is likely to be |
| A. | 10 A |
| B. | 7.07 A |
| C. | 6.35 A |
| D. | 3.5 A |
| Answer» B. 7.07 A | |
| 376. |
The signal x(t) = A cos (ω₀t + φ) is |
| A. | energy signal |
| B. | power signal |
| C. | energy Power |
| D. | none |
| Answer» C. energy Power | |
| 377. |
L [f(t - a)] = F(jω) e^(-jωa) |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 378. |
The integral of k δ(t) is |
| A. | a step function of magnitude k |
| B. | a step function of magnitude 1/k |
| C. | a ramp of slope k |
| D. | a ramp of slope 1/k |
| Answer» B. a step function of magnitude 1/k | |
| 379. |
In the periodic train of rectangular pulses F₀ = (V₀/T)d |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't Say |
| Answer» B. False | |
| 380. |
Consider the following and answer accordingly: |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 381. |
If v(t) is a time varying voltage, then following is |
| A. | initial current |
| B. | initial voltage |
| C. | initial charge |
| D. | initial flux leakages |
| Answer» E. | |
| 382. |
Fourier transform F(jω) of an arbitrary signal has the property |
| A. | F(jω) = F(- jω) |
| B. | F(jω) = - F(- jω) |
| C. | F(jω) = F*(- jω) |
| D. | F(jω) = - F*(jω) |
| Answer» C. F(jω) = F*(- jω) | |
| 383. |
If F[jω] is Fourier transform of f(t), then Fourier transform of f(- t) = |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 384. |
Which of the following is/are not a property/properties power spectral density function Sx(ω)? |
| A. | Sx(ω) is real function of ω |
| B. | Sx(ω) is a even function of ω |
| C. | Sx(ω) is non-positive function of ωSx(ω) ≤ 0 for all ω |
| D. | All of the above |
| Answer» D. All of the above | |
| 385. |
If L[f(t)] = 2(s+1)/ s²+2s+5 , then, f(0⁺) and f(∞) are given by |
| A. | 0 and 2 |
| B. | 2, 0 |
| C. | 0, 1 |
| D. | 2/5, 0 |
| Answer» C. 0, 1 | |
| 386. |
A wave f(t) has half wave symmetry and time period equal to T. Then |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 387. |
A signal m(t) is multiplied by a sinusoidal waveform of frequency fc such thatv(t)=m(t) cos 2πfctIf Fourier transform of m(t) is M(f), Fourier transform of v(t) will be |
| A. | 0.5 M(f + fc) |
| B. | 0.5 M(f - fc) |
| C. | 0.5 M(f + fc) + 0.5 M(f - fc) |
| D. | 0.5 M(f - fc) + 0.5 M(f - fc) |
| Answer» D. 0.5 M(f - fc) + 0.5 M(f - fc) | |
| 388. |
The impulse response of the DT - LTI system is given below.Check whether the system is1. Stable2. Casual3.Dynamic |
| A. | 1 and 2 |
| B. | 2 and 3 |
| C. | 1 and 3 |
| D. | 1, 2 and 3 |
| Answer» E. | |
| 389. |
The given figure shows a discrete time system consisting of a unit delay system, a multiplier and a summer, such that y(k) = x(k - 1) + 0.5 x(k). This system |
| A. | is linear |
| B. | is non linear |
| C. | may be linear or non linear depending on value |
| D. | impossible to judge |
| Answer» B. is non linear | |
| 390. |
Choose the function f(t), - ∞ < t < + ∞, 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 | |
| 391. |
Consider following statements: |
| 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 | |
| 392. |
The function shown in the given Figure can be written as |
| A. | sum of two sinusoidal functions |
| B. | sum of two sinusoidal functions one originating at t = 0 and the other at t = 1 |
| C. | difference of two sinusoidal functions one originating at t = 0 and the other at t = 1 |
| D. | none of the above |
| Answer» E. | |
| 393. |
cos(nω1t) = |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 394. |
The function sinc x is equal to |
| A. | sinx/x |
| B. | x sinx |
| C. | x² sinx |
| D. | x / sinx |
| Answer» B. x sinx | |
| 395. |
In Laplace transform, multiplication by e^(-at) in time domain becomes |
| A. | translation by a in s domain |
| B. | translation by (-a) in s domain |
| C. | multiplication by e^(-as) in s domain |
| D. | none of the above |
| Answer» B. translation by (-a) in s domain | |
| 396. |
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 | |
| 397. |
If δ(t) denotes a unit impulse, Laplace transform of d²/dt²[δ(t)] is |
| A. | 1 |
| B. | s² |
| C. | s |
| D. | s¯² |
| Answer» C. s | |
| 398. |
The function Ae^[(s + jω)t] represens a rotating phasor having a magnitude increasing with time. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 399. |
If autocorrelation sequence is Rc(n) = {1,2,3,4,6,8} then what will be energy of sequence? |
| A. | 2 |
| B. | 24 |
| C. | 3 |
| D. | 288 |
| Answer» D. 288 | |
| 400. |
If f(t) = 1, F(jω) = |
| A. | 2π |
| B. | π |
| C. | 2πδ (π) |
| D. | πδ (ω) |
| Answer» D. πδ (ω) | |