MCQOPTIONS
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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.
| 201. |
Inverse Fourier Transform of δ(ω - ω0) is ______. |
| A. | \(\frac{2π}{e^{jω_0}t}\) |
| B. | \(e^{jω_0t}\) |
| C. | \(\frac {e^{jω_0t}}{2\pi}\) |
| D. | \(2\pi e^{jω_0t}\) |
| Answer» D. \(2\pi e^{jω_0t}\) | |
| 202. |
Consider a signal x(t) = 2r(t) – 2r(t - 2) – 4u(t - 4), evaluate \(\mathop \smallint \limits_{ - \infty }^\infty x\left( t \right)\delta \left( {t - 3} \right)\) |
| A. | 3 |
| B. | 4 |
| C. | 0 |
| D. | -4 |
| Answer» C. 0 | |
| 203. |
If a signal f(t) has energy E, the energy of the signal f(2t) is equal to |
| A. | E |
| B. | E/2 |
| C. | 2E |
| D. | 4E |
| Answer» C. 2E | |
| 204. |
A function which completes a pattern within a measurable time frame and repeats that pattern over identical subsequent time frames is called |
| A. | Continuous function |
| B. | Cyclic function |
| C. | Periodic function |
| D. | Recurrent function |
| Answer» D. Recurrent function | |
| 205. |
A unit impulse function is defined as1. a pulse of area 12. a pulse compressed along the horizontal axis and stretched along vertical axis keeping the area unity3. \(\frac{{du}}{{dt}}\)4. δ(t) = 0, t ≠ 0Which of the above statements are correct? |
| A. | 1, 2 and 3 only |
| B. | 1, 3 and 4 only |
| C. | 2, 3 and 4 only |
| D. | 1, 2, 3 and 4 |
| Answer» E. | |
| 206. |
If a system produces frequencies in the output that are not present in the input, then the system cannot be |
| A. | Minimum phase system |
| B. | Linear shift-invariant |
| C. | Stable and causal |
| D. | Stable and linear |
| Answer» C. Stable and causal | |
| 207. |
Match List-I with List-II and select the correct answer using the code given below the Lists:List - IList – IIA. Even signal1. \((\frac{1}{4})^{n} ~u(n)\)B. Casual signal2. x(-n) = x(n)C. Periodic signal3. x(t) u(t)D. Energy signal4. x(n) = x(n + N) |
| A. | A – 2, B – 3, C – 4, D - 1 |
| B. | A – 1, B – 3, C – 4, D - 2 |
| C. | A – 2, B – 4, C – 3, D - 1 |
| D. | A – 1, B – 4, C – 3, D - 2 |
| Answer» B. A – 1, B – 3, C – 4, D - 2 | |
| 208. |
A. If the inputs to control systems are gradually changing functions of time, then a/an _____ will be a good test signal.B. If a system is subjected to sudden disturbances, a/an _____ function will be a good test signal.C. For a system subjected to shock inputs a/an _____function will be a good test signal |
| A. | impulse, ramp, step |
| B. | ramp, step, impulse |
| C. | impulse, step, ramp |
| D. | ramp, impulse, step |
| Answer» C. impulse, step, ramp | |
| 209. |
If the input to a differentiating circuit is saw -tooth wave then output will be-----------wave |
| A. | Square |
| B. | Rectangular |
| C. | Triangular |
| D. | Saw-tooth |
| Answer» C. Triangular | |
| 210. |
An LTI system with unit sample response h[n] = 5δ[n] - 7δ [n - 1] + 7δ [n - 3] - 5δ [n - 4] is a |
| A. | low-pass filter |
| B. | high-pass filter |
| C. | band-pass filter |
| D. | band-stop filter |
| Answer» D. band-stop filter | |
| 211. |
Directions: The below item consists of two statements, one labelled as the 'Statement (I)' and the other as 'Statement (II)'. Examine these two statements carefully and select the answers to these items using the codes given below:Statement (I): The total energy of an energy signal falls between the limits 0 and ∞.Statement (II): The average power of an energy signal is zero.Codes: |
| A. | Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I) |
| B. | Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I) |
| C. | Statement (I) is true but Statement (II) is false |
| D. | Statement (I) is false but Statement (II) is true |
| Answer» C. Statement (I) is true but Statement (II) is false | |
| 212. |
A continuous-time function x(t) is periodic with period T. The function is sampled uniformly with a sampling period Ts. In which one of the following cases is the sampled signal periodic? |
| A. | \(T = \sqrt 2 \;{T_s}\) |
| B. | T = 1.2 Ts |
| C. | Always |
| D. | Never |
| Answer» C. Always | |
| 213. |
An unit impulse function in continuous form is defined to be |
| A. | δ(t) = t |
| B. | δ(t) = 1 |
| C. | \(\delta \left( t \right) = \left\{ {\begin{array}{*{20}{c}}{\infty ,\;\;t = 0}\\{0,\;\;t \ne 0}\end{array}} \right.\) |
| D. | \(\delta \left( t \right) = \left\{ {\begin{array}{*{20}{c}}{0,\;\;t = 0}\\{1,\;\;t \ne 0}\end{array}} \right.\) |
| Answer» D. \(\delta \left( t \right) = \left\{ {\begin{array}{*{20}{c}}{0,\;\;t = 0}\\{1,\;\;t \ne 0}\end{array}} \right.\) | |
| 214. |
Identify the nature of the signal shown in the given image. |
| A. | Odd signals |
| B. | Periodic signals |
| C. | Even signals |
| D. | Aperiodic signals |
| Answer» B. Periodic signals | |
| 215. |
A function f(t) is said to be even if: |
| A. | f(t) = f(-t) |
| B. | f(t) = -f(-t) |
| C. | f(t) ≠ f(-t) |
| D. | None of these |
| Answer» B. f(t) = -f(-t) | |
| 216. |
A signal is said to be1. Deterministic if there is no uncertainty over the signal at any instant of time.2. Deterministic if it is expressible through a mathematical equation.3. Random or non-deterministic if there is uncertainty over the signal at the instant of time.4. Random or non-deterministic if it is not expressible through a mathematical equation.Which of the above statements are correct? |
| A. | 1, 2 and 3 only |
| B. | 1, 2 and 4 only |
| C. | 3 and 4 only |
| D. | 1, 2, 3 and 4 |
| Answer» E. | |
| 217. |
If f(t) ↔ F(jω), and f(t) is real, then |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 218. |
If X(z) = (1 - a)z¯¹/[(1 - z¯¹)(1 - az¯¹)] and 1 < |z|, the final value of xk is |
| A. | 0 |
| B. | 1 |
| C. | ∞ |
| D. | 2 |
| Answer» C. ∞ | |
| 219. |
The range of value "a" for which system will be stable. If impulse response of DT system is = aⁿ ∪[n] |
| A. | a > 1 |
| B. | a < 1 |
| C. | 1 < a < ∞ |
| D. | -1 < a < 1 |
| Answer» E. | |
| 220. |
A casual system having the transfer function H(s) = 1/(s+2) is excited with 10 ∪(t). The time at which the output reaches 99% of its steady-state value is |
| A. | 2.7 sec |
| B. | 2.5 sec |
| C. | 2.3 sec |
| D. | 2.1 sec |
| Answer» D. 2.1 sec | |
| 221. |
The energy associated with a function f(t) is given below. In terms of Fourier transform, E = |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 222. |
In what range should Re(s) remains so that Laplace transform of the function e^[(a + 2)t + 5] exists? |
| A. | Re(s) > a + 2 |
| B. | Re(s) > a + 7 |
| C. | Re(s) < a |
| D. | Re(s) > a + 5 |
| Answer» B. Re(s) > a + 7 | |
| 223. |
The Laplace transform of a vlotage across a capacitor is Vc (s) = 1 / s²+1 . If capacitor is 0.5 F, The current through capacitor at t = 0⁺ is |
| A. | 0 A |
| B. | 2 A |
| C. | 0.5 A |
| D. | 1 A |
| Answer» D. 1 A | |
| 224. |
The DTFT of x(n) = δ(n) will be |
| A. | 1 |
| B. | 0 |
| C. | ∞ |
| D. | not defined |
| Answer» B. 0 | |
| 225. |
Laplace transforn of sin (ωt + a) is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 226. |
An excitation is applied to a system at t = T and the response in zero for -∞ < t < T. This system is |
| A. | non casual |
| B. | stable |
| C. | casual |
| D. | unstable |
| Answer» D. unstable | |
| 227. |
Auto correlation for τ = 0 is equal to |
| A. | average power S of waveform |
| B. | square of average power S of waveform |
| C. | half of average power S of waveform |
| D. | square root of average power S of waveform |
| Answer» B. square of average power S of waveform | |
| 228. |
If the system transfer function of a discrete time system H(z) = z/(z-1), then system is |
| A. | stable |
| B. | unstable |
| C. | stable at z = 1 |
| D. | unstable at z = 1 |
| Answer» B. unstable | |
| 229. |
If v(t) = 0 for t < 0 and v(t) = e^(-at) for t ≥ 0, V(jω) = |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 230. |
The ROC of sequence in the Z.T. of sequence x[n] = aⁿ ∪ [n] is |
| A. | z > a |
| B. | z < a |
| C. | |z| > a |
| D. | |z| < a |
| Answer» D. |z| < a | |
| 231. |
The impulse response of discrete time system is x[n] = (4)ⁿ ∪ [3 - n], the system is |
| A. | casual |
| B. | stable |
| C. | stable and casual |
| D. | stable and non-casual |
| Answer» E. | |
| 232. |
The inverse Laplace transform of 1/(s - a)² is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 233. |
Assertion (A): δ(t - b) is an impulse occuring at t = bReason (R): Intergal of unit impulse gives unit step function. |
| 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 | |
| 234. |
If F(s) is the Laplace transform of f(t) then Laplace transform of df(t)/dt = |
| A. | F(s)/s |
| B. | sFU(s) |
| C. | s²F(s) |
| D. | F(s)/s² |
| Answer» C. s²F(s) | |
| 235. |
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 | |
| 236. |
The range of values of a and b for which the linear time invariant system with impulse response. h(n) = aⁿ n ≥ 0 = bⁿ n < 0 will be stable if |
| A. | |a| > 1, |b| > 1 |
| B. | |a| < 1, |b| < 1 |
| C. | |a| < 1, |b| > 1 |
| D. | |a| > 1, |b| < 1 |
| Answer» D. |a| > 1, |b| < 1 | |
| 237. |
If I (s) = 5(s+250)/s(s+100) , the final value of i(t) is |
| A. | 5A |
| B. | 12.5 A |
| C. | 0.05 A |
| D. | 1250 A |
| Answer» C. 0.05 A | |
| 238. |
The eign values of n x n matrix A are the root of the characteristic equation 1λI - AI = 0 |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 239. |
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 | |
| 240. |
For matrix A, A¯¹ A = 1 |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 241. |
If xk = 2^k for k ≤ 0 and = 0 for k > 0 X(z) = 2/(2 - z). |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 242. |
If f(t) is an even function, F(jω) = |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 243. |
What about causality of the system transfer function of a discrete time system H(z) = z/(z-1) |
| A. | uncasual |
| B. | casual |
| C. | casual and some specific point |
| D. | Both b and c |
| Answer» C. casual and some specific point | |
| 244. |
If F(jω) is the Fourier transform of f(t), then |
| A. | £ f(- t) = F(jω) |
| B. | £ f(- t) = F* (jω) |
| C. | £ f(- t) = F(- jω) |
| D. | £ f(- t) = F* (- jω) |
| Answer» C. £ f(- t) = F(- jω) | |
| 245. |
e^(-3t) is a |
| A. | energy signal |
| B. | power signal |
| C. | Both (a) and (b) |
| D. | none |
| Answer» E. | |
| 246. |
(sI - A)¯¹ is equal to |
| A. | adj (sI - A)/det (sI - A) |
| B. | det (sI - A)/adj(sI - A ) |
| C. | [adj (sI - A)] [det(sI - A)] |
| D. | none of the above |
| Answer» B. det (sI - A)/adj(sI - A ) | |
| 247. |
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. | |
| 248. |
An experiment is repeated N times. One event A occurs Nᴀ times. Then |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 249. |
If two mutually exclusive events A and B can happen in m and n ways, then either A or B can happen in (m + n) ways. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 250. |
δ(t - b) is a pulse function. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» C. May be True or False | |