MCQOPTIONS
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MCQOPTIONS
This section includes 76 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The impulse response of discrete-time signal is given by h [n] = u [n+3]. Whether the system is causal or not? |
| A. | causal |
| B. | non-causal |
| C. | insufficient information |
| D. | the system cannot be classified |
| Answer» C. insufficient information | |
| 2. |
Causal systems are |
| A. | anticipative |
| B. | non anticipative |
| C. | for certain cases anticipative |
| D. | for certain cases anticipative and non anticipative |
| Answer» C. for certain cases anticipative | |
| 3. |
The causal continuous system with impulse response should satisfy          equation. |
| A. | h(t)=0,t<0 |
| B. | h(t)=0,t>0 |
| C. | h(t)≠0,t<0 |
| D. | h(t)≠0,t≤0 |
| Answer» B. h(t)=0,t>0 | |
| 4. |
The condition for memory-less system is given by |
| A. | h[k] = cδ[k] |
| B. | h[k] = cδ[n-k] |
| C. | h[k] = ch[k]δ[k] |
| D. | h[k] = ch[n-k]δ[k] |
| Answer» B. h[k] = cδ[n-k] | |
| 5. |
When two LTI systems with impulse responses ha (t) and hb (t) are cascaded then equivalent response is given by |
| A. | h(t) = ha(t) + hb(t) |
| B. | h(t) = ha(t) – hb(t) |
| C. | h(t) = ha(t) hb(t) |
| D. | h(t) = ha(t) * hb(t) |
| Answer» E. | |
| 6. |
If two LTI systems with impulse response h1 (t) and h2 (t) and are connected in parallel then output is given by |
| A. | y(t) = x(t) *(h1(t) + h2(t)) |
| B. | y(t) = x(t) + (h1(t) + h2(t)) |
| C. | y(t) = x(t) * (h1(t) h2(t)) |
| D. | y(t) = (x(t) * h1(t)) + h2(t) |
| Answer» B. y(t) = x(t) + (h1(t) + h2(t)) | |
| 7. |
What is the Scope value if the signal generator has a frequency of 2 Hz only? |
| A. | an attenuated signal of same frequency |
| B. | the entire signal at the same frequency |
| C. | the entire signal at reduced frequency |
| D. | an attenuated signal at reduced frequency |
| Answer» B. the entire signal at the same frequency | |
| 8. |
A continuous signal can be represented as the product of an impulse function and the signal itself. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 9. |
The convolution of a function with an impulse function delayed to an instant 3 in time results in |
| A. | an advance in the function by 3 units in time |
| B. | the function itself |
| C. | a delay in the function by 3 units in time |
| D. | cannot be determined |
| Answer» D. cannot be determined | |
| 10. |
The convolution of a discrete signal with itself is |
| A. | squaring the signal |
| B. | doubling the signal |
| C. | adding two signals |
| D. | is not possible |
| Answer» B. doubling the signal | |
| 11. |
For a causal L.T.I. system, the impulse response is 0 for |
| A. | t<0 |
| B. | t=0 |
| C. | t>0 |
| D. | always |
| Answer» B. t=0 | |
| 12. |
Impulse response is the output of              system due to impulse input applied at time=0? |
| A. | linear |
| B. | time varying |
| C. | time invariant |
| D. | linear and time invariant |
| Answer» E. | |
| 13. |
The system described by the difference equation y(n) – 2y(n-1) + y(n-2) = X(n) – X(n-1) has y(n) = 0 and n |
| A. | 2 |
| B. | 1 |
| C. | -1 |
| Answer» D. | |
| 14. |
A Discrete signal is said to be even or symmetric if X(-n) is equal to |
| A. | x(n) |
| B. | 0 |
| C. | –x(n) |
| D. | –x(-n) |
| Answer» B. 0 | |
| 15. |
Then, y[k] = x[3k-2] is |
| A. | y[k] = 1, for k = 0, 1 and 0 otherwise |
| B. | y[k] = 1, for k = 1 and -1 for k=-1 |
| C. | y[k] = 1, for k = 0, 1 and -1 otherwise |
| D. | y[k] = 1, for k = 0, 1 and 0 otherwise |
| Answer» B. y[k] = 1, for k = 1 and -1 for k=-1 | |
| 16. |
The Fourier series for the function f (x) = sin2x is |
| A. | 0.5 + 0.5 sin 2x |
| B. | 0.5 – 0.5 sin 2x |
| C. | 0.5 + 0.5 cos 2x |
| D. | 0.5 – 0.5 cos 2x |
| Answer» E. | |
| 17. |
Find the convolution sum of sequences x1[n] = (1, 2, 3) and x2[n] = (2, 1, 4). |
| A. | {2, 5, 12, 11, 12} |
| B. | {2, 12, 5, 11, 12} |
| C. | {2, 11, 5, 12, 12} |
| D. | {-2, 5,-12, 11, 12} |
| Answer» B. {2, 12, 5, 11, 12} | |
| 18. |
Weighted superposition of time-shifted impulse responses is termed as                for discrete-time signals. |
| A. | convolution integral |
| B. | convolution multiple |
| C. | convolution sum |
| D. | convolution |
| Answer» D. convolution | |
| 19. |
Which of the following is correct regarding to impulse signal? |
| A. | x[n]δ[n] = x[0]δ[n] |
| B. | x[n]δ[n] = δ[n] |
| C. | x[n]δ[n] = x[n] d) x[n]δ[n] = x[0] |
| Answer» B. x[n]δ[n] = δ[n] | |
| 20. |
How does Fourier series make it easier to represent periodic signals? |
| A. | harmonically related |
| B. | periodically related |
| C. | sinusoidally related |
| D. | exponentially related |
| Answer» B. periodically related | |
| 21. |
What is the disadvantage of exponential Fourier series? |
| A. | it is tough to calculate |
| B. | it is not easily visualized |
| C. | it cannot be easily visualized as sinusoids |
| D. | it is hard for manipulation |
| Answer» D. it is hard for manipulation | |
| 22. |
Fourier series uses which domain representation of signals? |
| A. | time domain representation |
| B. | frequency domain representation |
| C. | both combined |
| D. | neither depends on the situation |
| Answer» C. both combined | |
| 23. |
Fourier series is not true in case of discrete time signals. |
| A. | true |
| B. | false |
| Answer» C. | |
| 24. |
What is a line spectrum? |
| A. | plot showing magnitudes of waveforms are called line spectrum |
| B. | plot showing each of harmonic amplitudes in the wave is called line spectrum |
| C. | plot showing each of harmonic amplitudes in the wave is called line spectrum |
| D. | plot showing each of harmonic amplitudes called line spectrum |
| Answer» C. plot showing each of harmonic amplitudes in the wave is called line spectrum | |
| 25. |
What is the polar form of the fourier series? |
| A. | x(t) = c0 + ∑cncos(nwt+ϕn) |
| B. | x(t) = c0 + ∑cncos(ϕn) |
| C. | x(t) = ∑cncos(nwt+ϕn) |
| D. | x(t) = c0+ ∑cos(nwt+ϕn) |
| Answer» B. x(t) = c0 + ∑cncos(Ï•n) | |
| 26. |
Which are the fourier coefficients in the following? |
| A. | a0, an and bn |
| B. | an |
| C. | bn |
| D. | an and bn |
| Answer» B. an | |
| 27. |
The fourier series coefficients of the signal are carried from –T/2 to T/2. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 28. |
Do exponential fourier series also have fourier coefficients to be evaluated. |
| A. | true |
| B. | false |
| Answer» B. false | |
| 29. |
All causal systems must have the component of |
| A. | memory |
| B. | time invariance |
| C. | stability |
| D. | linearity |
| Answer» B. time invariance | |
| 30. |
What are fourier coefficients? |
| A. | the terms that are present in a fourier series |
| B. | the terms that are obtained through fourier series |
| C. | the terms which consist of the fourier series along with their sine or cosine values |
| D. | the terms which are of resemblance to fourier transform in a fourier series are called fourier series coefficients |
| Answer» D. the terms which are of resemblance to fourier transform in a fourier series are called fourier series coefficients | |
| 31. |
When we take up design of systems, ideally how do we define the stability of a system? |
| A. | a system is stable, if a bounded input gives a bounded output, for some values of the input |
| B. | a system is unstable, if a bounded input gives a bounded output, for all values of the input |
| C. | a system is stable, if a bounded input gives a bounded output, for all values of the input |
| D. | a system is unstable, if a bounded input gives a bounded output, for some values of the input |
| Answer» D. a system is unstable, if a bounded input gives a bounded output, for some values of the input | |
| 32. |
A system is said to be defined as non causal, when |
| A. | the output at the present depends on the input at an earlier time |
| B. | the output at the present does not depend on the factor of time at all |
| C. | the output at the present depends on the input at the current time |
| D. | the output at the present depends on the input at a time instant in the future |
| Answer» E. | |
| 33. |
Should real time instruments like oscilloscopes be time invariant? |
| A. | yes |
| B. | sometimes |
| C. | never |
| D. | they have no relation with time variance |
| Answer» B. sometimes | |
| 34. |
A system which is linear is said to obey the rules of |
| A. | scaling |
| B. | additivity |
| C. | both scaling and additivity |
| D. | homogeneity |
| Answer» D. homogeneity | |
| 35. |
All real time systems concerned with the concept of causality are |
| A. | non causal |
| B. | causal |
| C. | neither causal nor non causal |
| D. | memoryless |
| Answer» C. neither causal nor non causal | |
| 36. |
A time invariant system is a system whose output |
| A. | increases with a delay in input |
| B. | decreases with a delay in input |
| C. | remains same with a delay in input |
| D. | vanishes with a delay in input |
| Answer» D. vanishes with a delay in input | |
| 37. |
An example of a discrete set of information/system is |
| A. | the trajectory of the sun |
| B. | data on a cd |
| C. | universe time scale |
| D. | movement of water through a pipe |
| Answer» C. universe time scale | |
| 38. |
The type of systems which are characterized by input and the output capable of taking any value in a particular set of values are called as |
| A. | analog |
| B. | discrete |
| C. | digital |
| D. | continuous |
| Answer» E. | |
| 39. |
Is the signal x(n) = u(n + 4) – u(n – 4) causal? |
| A. | yes |
| B. | no |
| Answer» C. | |
| 40. |
Is the signal x(t)= eat u(t) causal? |
| A. | yes |
| B. | no |
| Answer» B. no | |
| 41. |
Is the following signal an energy signal? x(t) = u(t) – u(t – 1) |
| A. | yes |
| B. | no |
| Answer» B. no | |
| 42. |
Determine the power of the signal: x(t) = cos(t). |
| A. | 1/2 |
| B. | 1 c) 3/2 |
| C. | d) 2 |
| Answer» B. 1 c) 3/2 | |
| 43. |
A signal is anti-causal if |
| A. | x(t) = 0 for t = 0 |
| B. | x(t) = 1 for t < 0 |
| C. | x(t) = 1 for t > 0 |
| D. | x(t) = 0 for t > 0 |
| Answer» E. | |
| 44. |
For an energy signal |
| A. | e=0 |
| B. | p= ∞ |
| C. | e= ∞ |
| D. | p=0 |
| Answer» E. | |
| 45. |
Is the signal sin(t) anti-symmetric? |
| A. | yes |
| B. | no |
| Answer» B. no | |
| 46. |
Determine the odd component of the signal: x(t)=cost+sint. |
| A. | sint |
| B. | 2sint |
| C. | cost |
| D. | 2cost |
| Answer» D. 2cost | |
| 47. |
Determine the Time period of: x(t)=3 cos(20t+5)+sin(8t-3). |
| A. | 1/10 sec |
| B. | 1/20 sec |
| C. | 2/5 sec d 2/4 sec |
| Answer» D. | |
| 48. |
Most of the signals found in nature are |
| A. | continuous-time and discrete-time |
| B. | continuous-time and digital |
| C. | digital and analog |
| D. | analog and continuous-time |
| Answer» E. | |
| 49. |
Sum of two periodic signals is a periodic signal when the ratio of their time periods is |
| A. | a rational number |
| B. | an irrational number |
| C. | a complex number |
| D. | an integer |
| Answer» B. an irrational number | |
| 50. |
Which one of the following is not a characteristic of a deterministic signal? |
| A. | exhibits no uncertainty |
| B. | instantaneous value can be accurately predicted |
| C. | exhibits uncertainty |
| D. | can be represented by a mathematical equation |
| Answer» D. can be represented by a mathematical equation | |