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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.
| 751. |
An RLC series circuit has a variable inductance. The value of L for resonance conditions at fundamental frequency is 0.18 H. For resonance conditions at third harmonic frequency the value of inductance is |
| A. | 0.54 H |
| B. | 0.06 H |
| C. | 0.02 H |
| D. | 1.62 H |
| Answer» D. 1.62 H | |
| 752. |
X and Y are two random variables and Z = X + Y . Letmz, mz, mx, my represent mean of Z, X and Y. Then |
| A. | mz = mx + my |
| B. | mz ≤ mx + my |
| C. | mz< mx + my |
| D. | mz > mx + my |
| Answer» B. mz ‚⧠mx + my | |
| 753. |
A discrete LTI system is non-casual if its impulse response is |
| A. | an ‚à™(n - 2) |
| B. | an-2 ‚à™(n) |
| C. | an+2 ‚à™(n) |
| D. | an ‚à™(n + 2) |
| Answer» E. | |
| 754. |
The analog signal given below is sampled by 600 samples per second for m(t) = 3 sin 500 pt + 2 sin 700 pt then folding frequency is |
| A. | 500 Hz |
| B. | 700 Hz |
| C. | 300 Hz |
| D. | 1400 Hz |
| Answer» D. 1400 Hz | |
| 755. |
Algebraic expression for z-transform of x[n] is X[z]... What is the algebraic expression of z-transform of ejω0n x[n]? |
| A. | X(Z - Z0) |
| B. | X(e-jW0z) |
| C. | X(ejω0z) |
| D. | X(Z)jω0z |
| Answer» C. X(ejœâ0z) | |
| 756. |
The F.T. of a conjugate symmetric function is always |
| A. | imaginary |
| B. | real |
| C. | conjugate Unsymmetric |
| D. | conjugate symmetric |
| Answer» C. conjugate Unsymmetric | |
| 757. |
The period of the function cos is |
| A. | |
| B. | 8s |
| Answer» C. | |
| 758. |
An impulse function consist of |
| A. | pure dc |
| B. | pure a.c |
| C. | entire frequency range with constant phase |
| D. | infinite bandwidth with linear phase vaariations |
| Answer» D. infinite bandwidth with linear phase vaariations | |
| 759. |
If a linear time invartant system is exicited by a pure random signal like white noise, the output of the linear system will have which of the following properties? |
| A. | Output will be a white noise |
| B. | Output will be periodic |
| C. | Output will be random |
| D. | Output will be correlated or coloured noise |
| Answer» D. Output will be correlated or coloured noise | |
| 760. |
For formation of state equations, the inductors and current sources |
| A. | should be in tree |
| B. | should be in cotree |
| C. | may be in tree or cotree |
| D. | should be in both tree and cotree |
| Answer» C. may be in tree or cotree | |
| 761. |
F.T. of normalized Gaussian function e-pt2 is |
| A. | e-pf2 |
| B. | 2e-pt2 |
| Answer» B. 2e-pt2 | |
| 762. |
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 | |
| 763. |
For Ergodic Process |
| A. | ensemble Average equal to time Average |
| B. | ensemble Average is not equal to time Average |
| C. | ensemble Average > Time Average |
| D. | ensemble Average < Time Average |
| Answer» B. ensemble Average is not equal to time Average | |
| 764. |
Assertion (A): Reason (R): An impulse has a very high magnitude but very short duration. |
| 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 | |
| 765. |
The power in the signal s(t) = 8 cos (20 p - p/2) + 4 sin (15 pt) is |
| A. | 40 |
| B. | 41 |
| C. | 42 |
| D. | 82 |
| Answer» B. 41 | |
| 766. |
Which one is correct option about ROC? |
| A. | ROC does not contain any pole |
| B. | ROC of finite duration sequence is entire plane expect z = 0, z = ‚àû |
| C. | a and b |
| D. | only a |
| Answer» D. only a | |
| 767. |
Assertion (A): The unit impulse function is also known as Dirac delta function.Reason (R): If a voltage |
| 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 | |
| 768. |
The analog signal m(t) is given below m(t) = 4 cos 100 pt + 8 sin 200 pt + cos 300 pt, the Nyquist sampling rate will be |
| A. | 1/100 |
| B. | 1/200 |
| C. | 1/300 |
| D. | 1/600 |
| Answer» D. 1/600 | |
| 769. |
Z transform is a non-linear operation. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 770. |
In the given figure the ratio T/d is the duty factor. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 771. |
δ(t) is a |
| A. | energy signal |
| B. | power signal |
| C. | neither energy nor power |
| D. | none |
| Answer» C. neither energy nor power | |
| 772. |
Fourier series is applicable for |
| A. | periodic |
| B. | finite duration |
| C. | non periodic |
| D. | a and b |
| Answer» E. | |
| 773. |
The Nyquist sampling interval, for the signal sinc (700t) + sinc (500t) is |
| A. | 1/350 sec |
| B. | p/350 sec |
| C. | 1/700 sec |
| Answer» D. | |
| 774. |
Assertion (A): If , the final value of i(t) = 10Reason (R): If , the initial value i(t) = 2 |
| 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» E. | |
| 775. |
Which one is a linear system? |
| A. | y[n] = x[n] x x[n - 1] |
| B. | y[n] = x[n] + x[n - 10] |
| C. | y[n] = x2[n] |
| D. | (a) and (c) |
| Answer» C. y[n] = x2[n] | |
| 776. |
Assertion (A): The number ‚àà such that the probability that an error is between -‚àà and + ‚àà is 1 is called probable error of single obserevation. Reason (R): The standard deviation is the arms value of the deviation from the arithmetic mean. |
| 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 | |
| 777. |
Assertion (A): For the function shown in figureLaplace transform is Reason (R): |
| 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» B. Both A and R are correct but R is not correct explanation of A | |
| 778. |
Assertion (A): If , the initial value of i(t) is 5AReason (R): As per initial vaue theroem |
| 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» B. Both A and R are correct but R is not correct explanation of A | |
| 779. |
The impulse response h[n] of a linear time invariant system is given by h[n] = ‚à™[n + 3 ] + ‚à™[n - 2] -2‚à™[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 | |
| 780. |
If f1(t) |
| A. | a1F1(jω) + a2F2(jω) |
| B. | a1a2F1(jω) + F2(jω) |
| C. | a1F1(jω) - a2F2(jω) |
| D. | a1F1*(jω) + a2F2*(jω) |
| Answer» B. a1a2F1(jœâ) + F2(jœâ) | |
| 781. |
An ac circuit has an impedance of (3 + j6) ohm for fundamental. The impedance for fifth harmonic is |
| A. | (15 + j 30) Ω |
| B. | (15 + j 6) Ω |
| C. | (3 + j 30) Ω |
| D. | (3 + j 1.2) Ω |
| Answer» D. (3 + j 1.2) Œ© | |
| 782. |
Two rectangular waveforms of duration t1 and t2 seconds are convolved. What is the shape of the resulting waveform? |
| A. | Triangular |
| B. | Rectangular |
| C. | Trapezoidal |
| D. | Semi-circular |
| Answer» D. Semi-circular | |
| 783. |
A rectangular pulse is passed through an L.P.F. The response is a |
| A. | triangular |
| B. | trapezoidal function |
| C. | sampling |
| D. | Both (a) and (b) |
| Answer» B. trapezoidal function | |
| 784. |
which one is discrete time periodic signal? |
| A. | sin 3pn |
| B. | cos 2pn |
| C. | sin 3pn |
| D. | all |
| Answer» D. all | |
| 785. |
Pick the odd one |
| A. | variance |
| B. | standard deviation |
| C. | expectation |
| D. | chebyshev inequality |
| Answer» E. | |
| 786. |
The trignometric Fourier series of an even function of time does not have |
| A. | dc term |
| B. | cosine term |
| C. | sine term |
| D. | odd harmonic terms |
| Answer» D. odd harmonic terms | |
| 787. |
The minimum sampling frequency in sample/sec. required to reconstruct the following signal from its samples wuthout distortion would be |
| A. | 2 x 103 |
| B. | 4 x 103 |
| C. | 6 x 103 |
| D. | 8 x 103 |
| Answer» D. 8 x 103 | |
| 788. |
X and Y are two random variable and Z = X + Y. Let σx2, σy2 and σz2 be variance of X, Y and Z. Then |
| A. | σz2 = σx2 + σy2 |
| B. | σz2 ≤ σx2 + σy2 |
| C. | σz2 < σx2 + σy2 |
| D. | σz2 > σx2 + σy2 |
| Answer» B. œÉz2 ‚⧠œÉx2 + œÉy2 | |
| 789. |
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 | |
| 790. |
The inverse Laplace transform of 1/(s - a)2 is |
| A. | eat |
| B. | t eat |
| C. | t2 eat |
| D. | eat/t |
| Answer» C. t2 eat | |
| 791. |
If f(t) is an odd function |
| A. | 1 |
| B. | |
| Answer» C. | |
| 792. |
A voltage wave v = 10 + 20 sin ωt + 7.5 sin 3 ω(t) is applied to a series combination of two elements. The current is i = 5 sin (ωt + 20°) + 1.5 sin (3ωt + 10°). The elements are |
| A. | R and C |
| B. | R and L |
| C. | L and C |
| D. | both inductances |
| Answer» B. R and L | |
| 793. |
Inverse Laplace transform of is |
| A. | 2 exp (- 2.5 t) cosh (0.5 t) |
| B. | exp (- 2 t) + exp (- 3 t) |
| C. | 2 exp (- 2.5 t) sinh (0.5 t) |
| D. | 2 exp (- 2.5 t) cos 0.5 t |
| Answer» C. 2 exp (- 2.5 t) sinh (0.5 t) | |
| 794. |
F.T. of continuous non-periodic signal is |
| A. | aperiodic |
| B. | periodic |
| C. | a and b |
| D. | none |
| Answer» B. periodic | |
| 795. |
When a complex voltage wave is applied to a capacitor the resulting current wave is more distorted than the voltage wave. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 796. |
Assertion (A): Heaviside partial expansion gives a simple procedure to find inverse Laplace transform of the terms having a complex conjugate pair of roots.Reason (R): If I(s) = P(s)/Q(s) and all roots of Q(s) = 0 are simple, i(t) will have terms with exponentials having real exponents only. |
| 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 | |
| 797. |
Assertion (A): The function kest with both σ and ω positive and s > 0 depicts a sinusoid whose amplitude increases with time. Reason (R): If σ = 0, kest becomes a sinusoid. |
| 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 | |
| 798. |
Laplace transform of unit doublet is |
| A. | 1/s |
| B. | s2 |
| C. | s |
| D. | none |
| Answer» D. none | |
| 799. |
If is the Laplace transform of f(t) then f(0+) is |
| A. | 0 |
| B. | |
| C. | 27 |
| Answer» D. | |
| 800. |
The inverse response of a system h(n) = an‚à™(n) what is the condition for the system to be BIBO stable? |
| A. | a is real and +ve |
| B. | a is real and -ve |
| C. | |a| > 1 |
| D. | |a| < 1 |
| Answer» D. |a| < 1 | |