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.
| 801. |
A signal x(n) = sin(ω0n + φ) is the input to a linear time invariant system having a frequency response H(ejω) If the O/P of the system is Ax(n -n0), then the general form of H(ejω) will be |
| A. | #NAME? |
| B. | - n0ω0 + 2pk for any arbitrary integer k |
| C. | n0ω0 + 2pk for any arbitrary integer k |
| D. | #NAME? |
| Answer» C. n0œâ0 + 2pk for any arbitrary integer k | |
| 802. |
If |
| A. | -12 |
| B. | 12 |
| C. | 20 |
| D. | -20 |
| Answer» B. 12 | |
| 803. |
If the system transfer function of a discrete time system then system is |
| A. | stable |
| B. | unstable |
| C. | stable at z = 1 |
| D. | unstable at z = 1 |
| Answer» B. unstable | |
| 804. |
An excitation is applied to a system at t = T and the response in zero for -‚àû < t < T. This system is |
| A. | non casual |
| B. | stable |
| C. | casual |
| D. | unstable |
| Answer» D. unstable | |
| 805. |
An impulse train is |
| A. | a number of pulses |
| B. | a number of pulses spaced from each other |
| C. | a number of pulses all originating together |
| D. | none of the above |
| Answer» C. a number of pulses all originating together | |
| 806. |
L [f(t - a)] = F(jω) e-jωa |
| A. | 1 |
| B. | |
| C. | a step function of magnitude k |
| D. | a step function 'of magnitude 1/k |
| Answer» B. | |
| 807. |
The ROC of sequence x[n] = (0.8)n ‚à™[n] + (0.4)n ‚à™[n] |
| A. | |z| > 0.8 |
| B. | |z| > 0.4 |
| C. | 0.4 < |z| < 0.8 |
| D. | |z| < 0.8 |
| Answer» B. |z| > 0.4 | |
| 808. |
For a wave v = V 1m sin (ωt + θ1 ) - V3m sin (3ωt + θ3), the rms value is (0.5 V21m + 0.5 V23m)0.5 |
| A. | 1 |
| B. | |
| Answer» B. | |
| 809. |
An ac circuit has an impedance of (2 - j 9) Ω for third harmonic. The impedance for fundamental is |
| A. | 6 - j 27 Ω |
| B. | |
| C. | 2 - j 27 Ω |
| Answer» D. | |
| 810. |
Assertion (A): Standard deviation is the abscissa of a point of inflection on the probability curve.Reason (R): The equation for probability curve is |
| 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 | |
| 811. |
The function δ(t - b) is |
| A. | an impulse function |
| B. | a step function originating at t = b |
| C. | an impulse function originating at t = b |
| D. | none of the above |
| Answer» D. none of the above | |
| 812. |
A voltage v = 5 + 50 sin ωt/ + 5 sin 5 &omegat 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 | |
| 813. |
Two function g1(t) and g2(t) with correlation of 6 has average power of 4 and 5 respectively. The power of g1(t) + g2(t) is |
| A. | 9 |
| B. | 21 |
| C. | 3 |
| D. | 15 |
| Answer» C. 3 | |
| 814. |
The state equations are in the form |
| A. | X = AX + BW |
| B. | X = AX + Bu |
| C. | X = AX + Bx |
| D. | either (a) or (b) |
| Answer» B. X = AX + Bu | |
| 815. |
If f(t) ↔ F(jω), ↔ |
| A. | F(jω) |
| B. | [F(jω)]n |
| C. | (jω)n F(jω) |
| Answer» D. | |
| 816. |
If then system is |
| A. | casual |
| B. | uncasual |
| C. | casual at z = 0.4, 2 |
| D. | uncasual at z = 0.4, z = 2 |
| Answer» B. uncasual | |
| 817. |
Which of following is recursive system? |
| A. | y(n - 1) |
| B. | y(n + 1) |
| C. | y(n) |
| D. | y(n) + y(n + 1) |
| Answer» B. y(n + 1) | |
| 818. |
If £[f(t)] = F(s), then £[f(t - T)] = |
| A. | est F(s) |
| B. | e-st F(s) |
| Answer» C. | |
| 819. |
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 | |
| 820. |
If X(a) is the z transform of kxk, then the z transform of k xk is |
| A. | 1 |
| B. | |
| Answer» B. | |
| 821. |
If Laplace transform of f(t) is F(s), then £ f(t - a) u (t - a)= 0 |
| A. | eas F(s) |
| B. | e-as F(s) |
| C. | #NAME? |
| D. | #NAME? |
| Answer» C. #NAME? | |
| 822. |
If f(t) = 1, F(jω) = |
| A. | 2p |
| B. | p |
| C. | 2pδ (p) |
| D. | pδ (ω) |
| Answer» D. pŒ¥ (œâ) | |
| 823. |
For the signum function sgn(t), F(jω) = |
| A. | |
| B. | |
| Answer» C. | |
| 824. |
A voltage V(t) is a Gaussian ergodic random process with a mean of zero and a variance of 4 volt2. If it is measured by a dc meter. The reading will be |
| A. | 0 |
| B. | 4 |
| C. | 2 |
| D. | 2 |
| Answer» B. 4 | |
| 825. |
A signal m(t) with bandwidth 500 Hz is first multiplied by a signal g(t) where The resulting signal is then passed through on ideal low pass filter with bandwidth 1 kHz. The output of the low pass filter would me |
| A. | δ(t) |
| B. | m(t) |
| C. | 0 |
| D. | m(t) δ(t) |
| Answer» C. 0 | |
| 826. |
The function Ae(s + jω)t represens a rotating phasor having a magnitude increasing with time. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 827. |
consider the following as regards cumulative disribution function F(x)0 ≤ F(x) ≤ 1F(- ∞) = 0F(∞) = 1F(x1) ≤ F(x2) If x1 < x2 Out of above which are correct? |
| A. | 1 and 2 only |
| B. | 1, 2 and 3 only |
| C. | 1, 2, 3 and 4 |
| D. | 2 and 4 |
| Answer» D. 2 and 4 | |
| 828. |
If X(z) = (1 - az-1), and |a| < |z|, the initial value x0 is |
| A. | 1 |
| B. | 0 |
| C. | 2 |
| D. | ‚àû |
| Answer» B. 0 | |
| 829. |
Assertion (A): In order that f(t) is Laplace transformable, it is necessary that for real positive σ1 Reason (R): If f(t) is known we can find F(s) and vice versa. |
| 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 | |
| 830. |
Consider the following statements If ensemble and time averages of a random process are identical, the process is ergodic.If ensemble and time average of a random process are not identical, the process is ergodic.An ergodic process is stationary.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 | |
| 831. |
Which one is a non-causal system? |
| A. | y(n) = x(2n) |
| B. | y(n) = x(n/2) |
| C. | y(n) = x(n/2) + x(n) |
| D. | all |
| Answer» B. y(n) = x(n/2) | |
| 832. |
If I (s) , initial value of i(t) is |
| A. | 5A |
| B. | 12.5 A |
| C. | 0.05 A |
| D. | 1250 A |
| Answer» B. 12.5 A | |
| 833. |
If , the terms in f(t) will have |
| A. | e-t and e-2t |
| B. | et and e2t |
| C. | te-t and te-2t |
| D. | none of the above |
| Answer» B. et and e2t | |
| 834. |
The system with given pole-zero diagram is |
| A. | casual |
| B. | non-casual |
| C. | both sided |
| D. | not-possible |
| Answer» E. | |
| 835. |
As per time displacement theorem in Laplace transformation, displacement in the time domain by T becomes |
| A. | division by s in the s domain |
| B. | division by e-sT in the s domain |
| C. | multiplication by s in the s domain |
| D. | multiplication by e-sT in the s domain |
| Answer» E. | |
| 836. |
A system is stable if ROC |
| A. | include the unit circle |
| B. | exclude the unit circle |
| C. | lies on Circle |
| D. | entire plane |
| Answer» B. exclude the unit circle | |
| 837. |
δ(t) dt is a |
| A. | Unit step |
| B. | 0 |
| C. | r(t) |
| D. | sinc |
| Answer» B. 0 | |
| 838. |
The ROC of sequence in the Z.T. of sequence x[n] = an ‚à™ [n] is |
| A. | z > a |
| B. | z < a |
| C. | |z| > a |
| D. | |z| < a |
| Answer» D. |z| < a | |
| 839. |
Double integration of a unit step function would lead to |
| A. | an impulse |
| B. | a parabola |
| C. | a ramp |
| D. | a doublet |
| Answer» C. a ramp | |
| 840. |
The Z inverse of the given Z transform is |
| A. | Unit step |
| B. | Unit ramp |
| C. | Unit impulse |
| D. | Unit parabola |
| Answer» D. Unit parabola | |
| 841. |
In terms of signum function sgn(t), unit step function u(t) = |
| A. | 1 + sgn(t) |
| B. | 1 - sgn(t) |
| C. | 0.5 + 0.5 sgn(t) |
| D. | 0.5 - 0.5 sgn(t) |
| Answer» D. 0.5 - 0.5 sgn(t) | |
| 842. |
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 | |
| 843. |
Which one of following is a stataic system? |
| A. | y(n) = x(n) - x(n - 1) |
| B. | y(n) = x(2n) - x(2n-1) |
| C. | y(n) = x(n - 1) |
| D. | y(n) = ex(n) |
| Answer» E. | |
| 844. |
Let f1(t) = G1(t) + 4, f2(t) = G2(t) + 3. If G1(t) and G2(t) are uncorrected then the correlation between f1(t) and f2(t) are |
| A. | 12 |
| B. | 7 |
| C. | 6 |
| D. | zero |
| Answer» E. | |
| 845. |
Assertion (A): In complex frequency s = σ + jω, the terms s and ω are nepar frequency and radin frequency. Reason (R): If ω = 0, the graph of Kest will be a decaying exponential if s |
| 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 | |
| 846. |
The function in the given figure can be written as |
| A. | u(t - 1) sin p ( t - 1) - u(t - 3) sin p (t - 3) + u(t - 4) sin p (t - 4) - u(t - 6) sin p (t - 6) |
| B. | u(t - 1) sin p ( t - 1) - u(t - 3) sin p (t - 3) + u(t - 4) sin p (t - 4) |
| C. | u(t - 1) sin p ( t - 1) + u(t - 4) sin p (t - 4) |
| D. | u(t - 1) sin 2p ( t - 1) + u(t - 4) sin 2p (t - 4) |
| Answer» B. u(t - 1) sin p ( t - 1) - u(t - 3) sin p (t - 3) + u(t - 4) sin p (t - 4) | |
| 847. |
The inverse Fourier transform of the function F(ω) = is |
| A. | sin ωt |
| B. | cos ωt |
| C. | sgnt |
| D. | u(t) |
| Answer» D. u(t) | |
| 848. |
Which one of following is correct condition to check the stability of system? |
| A. | Bounded I/P unbounded O/P |
| B. | Bounded I/P and O/P |
| C. | Bounded O/P and I/P |
| D. | Bounded I/P Bounded O/P |
| Answer» C. Bounded O/P and I/P | |
| 849. |
If xk = 2k for k ≤ 0 and = 0 for k > 0 X(z) = 2/(2 - z). |
| A. | 1 |
| B. | |
| C. | a graph of complex number Fn versus frequency is plotted |
| D. | a graph of |Fn| versus frequency is plotted |
| Answer» B. | |
| 850. |
Fourier transform of an external exponential ejW0t |
| A. | δ(f - f0) |
| B. | 1 |
| C. | δ(f + f0) |
| D. | ‚àû |
| Answer» B. 1 | |