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MCQOPTIONS
This section includes 9294 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 6001. |
For the function f(t) = e-at, the Laplace transform is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/04-8-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/04-8-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/04-8-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/04-8-4.png"> |
| Answer» E. | |
| 6002. |
In a broadcast superheterodynes receiver having no RF amplifier, the loaded Q of the antenna coupling circuit is 100. If the intermediate frequency is 455 kHz. In receivers operating upto the limit of shortwave broadcasting the local oscillator often used is |
| A. | Armstrong oscillator |
| B. | Colpitts oscillator |
| C. | Clapp oscillator |
| D. | Ultra Audio oscillator |
| Answer» B. Colpitts oscillator | |
| 6003. |
Superheterodyne receiver can be used in |
| A. | AM |
| B. | FM |
| C. | SSB |
| D. | All of the above |
| Answer» E. | |
| 6004. |
Which of the following noise becomes of great importance at high frequencies? |
| A. | Transit-time noise |
| B. | Shot noise |
| C. | Flicker noise |
| D. | Agitation noise |
| Answer» B. Shot noise | |
| 6005. |
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 | |
| 6006. |
In an FM signal, the power |
| A. | increases as the modulation index increases |
| B. | reduces as the modulation index increase |
| C. | increases as the modulation index decreases |
| D. | remains constant when the modulation index increases |
| Answer» E. | |
| 6007. |
RF amplifiers are used in radio receivers for |
| A. | better sensitivity |
| B. | improved signal-to-noise ratio |
| C. | better coupling of receiver to the antenna |
| D. | all of the above |
| Answer» E. | |
| 6008. |
An unmodulated voltage 10 V effective is applied to a dioxide detector in which load resistance is 4 x 10-5 ohms. A micrometer shows that the rectified DC current in this resistance is 30 A. The efficiency of detection is |
| A. | 34% |
| B. | 55.5% |
| C. | 68.8% |
| D. | 84.7% |
| Answer» E. | |
| 6009. |
The selectivity curve of a standard receiver is represented by |
| A. | curve A |
| B. | curve B |
| C. | curve C |
| D. | curve D |
| Answer» D. curve D | |
| 6010. |
Which of the following statement about the advantage of phase discriminator over the slope detector is false? |
| A. | Fewer tuned circuits |
| B. | Better linearity |
| C. | Greater limiting |
| D. | Much easier alignment |
| Answer» D. Much easier alignment | |
| 6011. |
Fidelity of a receiver represents |
| A. | the sensitivity expressed in terms of voltage that must be applied to the receiver input to give a standard output |
| B. | the extent to which the receiver is capable of distinguishing between the desired signal and other frequencies |
| C. | the variation of the output with the modulation frequency when the output impedance is a resistance |
| D. | none of the above |
| Answer» D. none of the above | |
| 6012. |
Which of the following produces upper and lower side frequencies? |
| A. | Microphone |
| B. | Demodulator in a superheterodyne receiver |
| C. | Modulator in a. radio transmitter |
| D. | Oscillator in a receiver |
| Answer» B. Demodulator in a superheterodyne receiver | |
| 6013. |
In a superheterodyne receiver, the IF stage has better selectivity than RF stage because |
| A. | of higher frequency |
| B. | of lower frequency |
| C. | of high L/C ratio |
| D. | of constant passband |
| Answer» E. | |
| 6014. |
An arbitrary signal m (t) has zero average value and it is bandlimited to 3.2 kHz. It is sampled at the rate of 8 K samples/S. The samples are passed through an ideal bandpass filter with centre frequency of 32 kHz and bandwidth of 6.4 kHz. The output of band pass filter is |
| A. | AM-DSB signal with suppressed carrier |
| B. | AM-DSB signal with carrier |
| C. | AM-SSB signal with carrier |
| D. | a sequence of exponentially decaying sine waves |
| Answer» C. AM-SSB signal with carrier | |
| 6015. |
Selectivity varies with receiving frequency, frequency is raised. |
| A. | Somewhat better when the receiving frequency is raised |
| B. | Somewhat better at intermediate frequency |
| C. | Somewhat worse when the receiving frequency is lowered |
| D. | Somewhat worse when the receiving frequency is raised |
| Answer» E. | |
| 6016. |
The household radio receiver uses |
| A. | synchronous |
| B. | envelope detector |
| C. | radio detector |
| D. | none of the above |
| Answer» C. radio detector | |
| 6017. |
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 | |
| 6018. |
If Laplace transform of f(t) is F(s), then [tf(t)] = |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-87-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-87-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-87-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-87-4.png"> |
| Answer» C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-87-3.png"> | |
| 6019. |
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 | |
| 6020. |
Transfer function of a linear system is 200 e-j10 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 | |
| 6021. |
The z-transform of sequence n x x[n] is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/19-318-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/19-318-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/19-318-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/19-318-4.png"> |
| Answer» B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/19-318-2.png"> | |
| 6022. |
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. | |
| 6023. |
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 | |
| 6024. |
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 | |
| 6025. |
In the given figure shows a periodic triangular wave. The Fourier series will have |
| A. | all cosine terms |
| B. | all sine terms |
| C. | odd cosine terms |
| D. | odd sine terms |
| Answer» C. odd cosine terms | |
| 6026. |
If xk is one sided to the right |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6027. |
If F(j ) is the Fourier transform of f(t) then f(t) = |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-78-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-78-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-78-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-78-4.png"> |
| Answer» B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/07-78-2.png"> | |
| 6028. |
If f(t) is an even function |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6029. |
A stationary process has |
| A. | all statistical properties independent of time |
| B. | all statistical properties dependent of time |
| C. | zero variance |
| D. | ensemble average equal to time average |
| Answer» B. all statistical properties dependent of time | |
| 6030. |
If X(a) is the z transform of kxk, then the z transform of k xk is |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6031. |
The value of K in function f(x) = K(x - 1) for K = 1 < x < 4 |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/17-264-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/17-264-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/17-264-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/17-264-4.png"> |
| Answer» C. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/17-264-3.png"> | |
| 6032. |
A system is said to be static system, when present output depend upon |
| A. | present I/P |
| B. | presrent and past |
| C. | present and future |
| D. | past and future |
| Answer» B. presrent and past | |
| 6033. |
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 |
| Answer» B. False | |
| 6034. |
For formation of state equations, resistance of the circuit |
| A. | should be in tree |
| B. | should be in cotree |
| C. | may be in tree or cotree |
| D. | none of the above |
| Answer» D. none of the above | |
| 6035. |
In a Communication system, noise is most likely to affect the signal. |
| A. | at the transmitter |
| B. | In the channel |
| C. | in Information source |
| D. | at the destination |
| Answer» C. in Information source | |
| 6036. |
As per mormal distribution the probability of an error between limits a and b is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/09-122-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/09-122-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/09-122-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/09-122-4.png"> |
| Answer» B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/09-122-2.png"> | |
| 6037. |
The z transform of fk = ak is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/13-167-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/13-167-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/13-167-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/13-167-4.png"> |
| Answer» B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/13-167-2.png"> | |
| 6038. |
If the sequence |xn|1/n converges, then the series converages absolutely is |
| A. | Ratio test |
| B. | Root test |
| C. | Convergence test |
| D. | Divergence test |
| Answer» C. Convergence test | |
| 6039. |
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. | |
| 6040. |
A dice is tossed. The probability that either 1 or 2 will appear is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/15-217-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/15-217-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/15-217-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/15-217-4.png"> |
| Answer» D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/15-217-4.png"> | |
| 6041. |
In the given figure the phase angle of Fn is either 0 or . |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6042. |
The integral of a unit impulse is unit step function. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 6043. |
The tree selected for the formation of state equations contains |
| A. | all voltage sources |
| B. | all capacitors |
| C. | all inductors and current sources |
| D. | all voltage sources and maximum number of capacitors |
| Answer» E. | |
| 6044. |
If X(z) = (1 - az-1)-1 and |a| < |z|, the initial value x0 = 0 |
| A. | True |
| B. | False |
| Answer» C. | |
| 6045. |
Final value theorem is used to find |
| A. | steady state value of system output |
| B. | initial value of output |
| C. | transient beaviour of output |
| D. | none of these |
| Answer» B. initial value of output | |
| 6046. |
If xk = 0 for k < 0 and xk = 2k for k 3 0, X(z) i.e., Z transform of sequence x is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/08-104-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/08-104-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/08-104-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/08-104-4.png"> |
| Answer» B. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/08-104-2.png"> | |
| 6047. |
The region of converage of z-transform of sequence must be |
| A. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/21-362-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/21-362-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/21-362-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/21-362-4.png"> |
| Answer» D. <img src="/_files/images/electronics-and-communication-engineering/signals-and-systems/21-362-4.png"> | |
| 6048. |
If a function f(t) is an odd, function, its Fourier series |
| A. | contains only sine terms |
| B. | contains only cosine terms |
| C. | contains a constant and sine terms |
| D. | contains a constant and cosine |
| Answer» B. contains only cosine terms | |
| 6049. |
For a second order system, damping ratio is such that 0 < <. Then the roots of characteristic equation are |
| A. | real but not equal |
| B. | real and equal |
| C. | complex conjugate |
| D. | imaginary |
| Answer» D. imaginary | |
| 6050. |
A system has poles at 0.01 Hz, 1 Hz and 80 Hz, zeros at 5 Hz, 100 Hz and 200 Hz. The approximate phase of the system response at 20 Hz is |
| A. | -90 |
| B. | 0 |
| C. | 90 |
| D. | -180 |
| Answer» B. 0 | |