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.
| 851. |
If f(t) = A d(t - a), F(s) is |
| A. | A e-as |
| B. | A eas |
| C. | A a e-as |
| D. | Aa eas |
| Answer» B. A eas | |
| 852. |
In a network V(s) = Z(s) I(s) where V(s), Z(s) and I(s) are Laplace transforms of v(t), z(t) and i(t). The voltage v(t) is |
| A. | v(t) = z(t) i(t) |
| B. | |
| Answer» C. | |
| 853. |
A pole zero pattern of a certain filter is shown in figure. This filter must be |
| A. | LPF |
| B. | BFP |
| C. | HPF |
| D. | APF |
| Answer» E. | |
| 854. |
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. | 0.41666666666667 |
| B. | 7.07 A |
| C. | 6.35 A |
| D. | 3.5 A |
| Answer» B. 7.07 A | |
| 855. |
A voltage wave having 5% fifth harmonic content is applied to a series RC circuit. The percentage fifth harmonic content in the current wave will be |
| A. | 0.05 |
| B. | more than 5% |
| C. | less than 5% |
| D. | equal or more than 5% |
| Answer» C. less than 5% | |
| 856. |
If f(t) = - f(- t) satisfies Drichlet conditions, then f(t) can be expanded in Fourier series containing |
| A. | only sine terms |
| B. | only cosine terms |
| C. | cosine terms and constant |
| D. | sine terms and constant |
| Answer» B. only cosine terms | |
| 857. |
The inverse Laplace transform of |
| A. | eat |
| B. | #NAME? |
| C. | 1 - eat |
| D. | #NAME? |
| Answer» D. #NAME? | |
| 858. |
If a complex voltage wave is applied to a pure inductance, the resulting current wave is much smoother than the voltage wave. |
| A. | 1 |
| B. | |
| C. | |f(t)| e-σ1t dt < ∞ for a real positive σ1 |
| D. | |f(t)| e-σ1t dt < 0 for a real positive σ1 |
| Answer» B. | |
| 859. |
Assertion (A): Intergal of a unit step function is a ramp of slope unity.Reason (R): If |
| 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» D. A is false, R is true | |
| 860. |
Frequency domain of a periodic triangular function is a |
| A. | discrete sinc function |
| B. | continuous sampling function |
| C. | discrete sampling function |
| D. | continuous sampling square function |
| Answer» E. | |
| 861. |
The continuous time system with impulse response h(t) = is stable, for n is even, when |
| A. | a = 0 |
| B. | a > 0 |
| C. | a < 0 |
| D. | a ≤ 0 |
| Answer» D. a ‚⧠0 | |
| 862. |
The Laplace transform of a unit step function is |
| A. | 1 |
| B. | 1 / s |
| C. | s |
| D. | 1 / s2 |
| Answer» C. s | |
| 863. |
consider the following as regards probability distribution function f(x)f(x) = 0 for all xcumulative distribution function which of the above are correct? |
| A. | 1 only |
| B. | 1 and 2 only |
| C. | 1, 2 and 3 |
| D. | 1 and 3 only |
| Answer» D. 1 and 3 only | |
| 864. |
If a number of even functions are added, the resultant sum is |
| A. | even function |
| B. | odd funtion |
| C. | either even or odd function |
| D. | mixture of odd amd even functions |
| Answer» B. odd funtion | |
| 865. |
In a oscillator, a sine wave generator starts at t = 0. It consist of |
| A. | Pure sine wave |
| B. | Pure cosine wave |
| C. | Unity for t > 0 |
| D. | 2‚à™(t) - 1 |
| Answer» B. Pure cosine wave | |
| 866. |
A casual LTI system is described by the difference equation 2y[n] = ay[n - 2] - 2x[n] + βx[n -1] The system is stable only if |
| A. | |a| = 2 |β| < 2 |
| B. | |a| > 2 |β| > 2 |
| C. | |a| < 2 any value of β |
| D. | |β| < 2, any value of a |
| Answer» D. |Œ≤| < 2, any value of a | |
| 867. |
If p is the probability of success and q is the probability of failure, then the probability that there are r successes in n trails is |
| A. | ncr pr qn - r |
| B. | ncr pn - r qr |
| C. | ncr pr qn + r |
| D. | ncr pn qn - r |
| Answer» B. ncr pn - r qr | |
| 868. |
A first order system will never be able to give a __________ response band stopband passall 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 | |
| 869. |
If i(t) is a time varying current, is |
| A. | initial current |
| B. | initial charge |
| C. | initial flux leakages |
| D. | initial voltage |
| Answer» C. initial flux leakages | |
| 870. |
Let be the Fourier transform of y(n), then y(ej0) is |
| A. | 43556 |
| B. | 2 |
| C. | 4 |
| D. | 43528 |
| Answer» B. 2 | |
| 871. |
If , the coefficient of term e-t in f(t) will be |
| A. | 1 |
| B. | 0 |
| C. | 0.5 |
| D. | 43526 |
| Answer» E. | |
| 872. |
The Fourier series of an odd periodic function contains |
| A. | odd harmonics only |
| B. | even harmonics only |
| C. | cosine harmonics only |
| D. | sine harmonics only |
| Answer» E. | |
| 873. |
Fourier transform is defined for |
| A. | periodic |
| B. | non-periodic |
| C. | finite duration |
| D. | all |
| Answer» C. finite duration | |
| 874. |
The peak factor is |
| A. | rms value/peak value |
| B. | rms value/average value |
| C. | peak value/rms value |
| D. | peak to peak value/rms value |
| Answer» D. peak to peak value/rms value | |
| 875. |
A signal is sampled at Nyquist rate fs = 2f0. The function can be recovered from its samples only. If it is a |
| A. | Periodic square wave of fundamental frequency f0 |
| B. | Triangular wave of fundamental frequency f0 |
| C. | Periodic sine wave of fundamental frequency f0 |
| D. | Unit impulse function |
| Answer» D. Unit impulse function | |
| 876. |
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 | |
| 877. |
FIR filter Passes __________ Phase. |
| A. | non-linear phase |
| B. | linear phase |
| C. | variable phase |
| D. | none |
| Answer» B. linear phase | |
| 878. |
Inverse Fourier transform of sgn (ω) is |
| A. | |
| B. | 1 |
| Answer» B. 1 | |
| 879. |
check the following system for causality y[n] = x[n] + 2x[n - 1]y[n] = x[n - k]y[n] = x[2n] |
| A. | (1) and (2) |
| B. | (2) and (3) |
| C. | (1) omly |
| D. | (1) and (3) |
| Answer» D. (1) and (3) | |
| 880. |
Choose the correct option |
| A. | var (X) = σx2 |
| B. | σ2 = E(X2) - μ2 |
| C. | var (CX) = C2 Var (X) |
| D. | all |
| Answer» E. | |
| 881. |
For the discrete time system of the given figure |
| A. | yk - 0.5 yk - 1 - 0.25 yk - 2 = uk |
| B. | yk + 0.5 yk - 1 - 0.25 yk - 2 = uk |
| C. | yk - 0.5 yk - 1 + 0.25 yk - 2 = uk |
| D. | yk + 0.5 yk - 1 + 0.25 yk - 2 = uk |
| Answer» D. yk + 0.5 yk - 1 + 0.25 yk - 2 = uk | |
| 882. |
If I (s) , 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 | |
| 883. |
Short circuit is the dual of open circuit. |
| A. | 1 |
| B. | |
| C. | 50 |
| D. | 100 |
| Answer» B. | |
| 884. |
If δ(t) denotes a unit impulse, Laplace transform of is |
| A. | 1 |
| B. | s2 |
| C. | s |
| D. | s-2 |
| Answer» C. s | |
| 885. |
The signal defined by the equations f(t) = 0 for t < 0, f(t) = E for 0 ≤ t ≤ a and f(t) = 0 for t > a is |
| A. | a step function |
| B. | a pulse function |
| C. | a shifted step function originating at t = a |
| D. | none of the above |
| Answer» C. a shifted step function originating at t = a | |
| 886. |
In an ac circuit the fundamental component of current wave lags the corresponding voltage wave by 20°. The third harmonic component of current wave lags the corresponding voltage by an angle. |
| A. | less than 20° |
| B. | more than 20° |
| C. | equal to 20° |
| D. | equal to or more than 20° |
| Answer» C. equal to 20¬∞ | |
| 887. |
Which one most appropriate dynamic system? |
| A. | y(n) + y(n - 1) + y(n + 1) |
| B. | y(n) + y(n - 1) |
| C. | y(n) = x(n) |
| D. | y(n) + y(n - 1) + y(n + 3) = 0 |
| Answer» B. y(n) + y(n - 1) | |
| 888. |
Which one is a causal system? |
| A. | y(n) = 3x[n] - 2x[n - 1] |
| B. | y(n) = 3x[n] + 2x[n + 1] |
| C. | y(n) = 3x[n + 1] + 2x[n - 1] |
| D. | y(n) = 3x[n + 1] 2x[n - 1] + x[n] |
| Answer» B. y(n) = 3x[n] + 2x[n + 1] | |
| 889. |
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 | |
| 890. |
The z-transform of a particular signal is given whereThe system after implementation will be |
| A. | casual and stable |
| B. | non-casual and stable |
| C. | non-casual and unstable |
| D. | casual and unstable |
| Answer» B. non-casual and stable | |
| 891. |
A signal m(t) is multiplied by a sinusoidal waveform of frequency fc such thatv(t)=m(t) cos 2pfctIf 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) | |
| 892. |
Transfer function of a linear system is 200 e-j10ω The system is a |
| A. | distortionless Attenuator |
| B. | amplifier with Phase distortion |
| C. | distortionless Amplifier |
| D. | attenuator with Phase distortion |
| Answer» D. attenuator with Phase distortion | |
| 893. |
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(- jœâ) | |
| 894. |
If then for this to be true x(t) is |
| A. | exp (j2p f/t) |
| B. | exp (-j2p f/t) |
| C. | exp (j2p ft) |
| D. | exp (-j2p f/t) |
| Answer» D. exp (-j2p f/t) | |
| 895. |
If f=0 |
| A. | XL = 0 and XC = 0 |
| B. | XL = ‚àû, XC = ‚àû |
| C. | XL = 0 and XC = ‚àû |
| D. | XL = ‚àû and XC = 0 |
| Answer» D. XL = ‚àû and XC = 0 | |
| 896. |
The total area under the probability distribution curve is |
| A. | 1 |
| B. | 0 |
| C. | depend upon curve equation |
| D. | ‚àû |
| Answer» B. 0 | |
| 897. |
A signal g(t) = A then g(t) is a |
| A. | energy signal |
| B. | power signal |
| C. | neither energy nor power signal |
| D. | insufficient data |
| Answer» C. neither energy nor power signal | |
| 898. |
If f(t) is in volts, then F(jω) is in |
| A. | volts |
| B. | volt seconds |
| C. | volts/sec |
| D. | volt-sec2 |
| Answer» C. volts/sec | |
| 899. |
An energy signal has G(f) = 10. Its energy density spectrum is |
| A. | 10 |
| B. | 100 |
| C. | 50 |
| D. | 20 |
| Answer» C. 50 | |
| 900. |
Let x(t) and y(t) with F.T. x(f) and y(f) respectively be related as shown in figure Then y(f) is |
| A. | |
| B. | |
| Answer» C. | |