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MCQOPTIONS
This section includes 519 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.
| 401. |
In a synchro transmitter-control transformer, the voltage induced in rotor winding of control transformer is zero when the angular displacement between rotors of transmitter and transformer is |
| A. | 0° |
| B. | 90° |
| C. | 180° |
| D. | either (a) or (c) |
| Answer» C. 180¬∞ | |
| 402. |
Assertion (A): The time response, usually, is slower with lag compensation. Reason (R): The natural undamped frequency and bandwidth are increased. |
| 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 correct but R is wrong |
| D. | R is correct but A is wrong |
| Answer» E. | |
| 403. |
For the transport lag G(jω) = e-jωT, the magnitude is always equal to |
| A. | 0 |
| B. | 1 |
| C. | 10 |
| D. | 0.5 |
| Answer» C. 10 | |
| 404. |
In the given figure, the input frequency is such that R = XC. Then |
| A. | v0 lags vi by 45° |
| B. | v0 lags vi by 90° |
| C. | v0 leads vi by 45° |
| D. | v0 leads vi by 90° |
| Answer» B. v0 lags vi by 90¬∞ | |
| 405. |
Assertion (A): If the Laplace transform is , the Laplaces transform of impulse response is given by Reason (R): The Laplace transform for an impulse function is 1. |
| 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 correct but R is wrong |
| D. | R is correct but A is wrong |
| Answer» B. Both A and R are correct but R is not correct explanation of A | |
| 406. |
In Bode diagram (log magnitude plot) the factor (jω)n in the transfer function gives a line having slope |
| A. | 20 dB/decade |
| B. | 20n dB/decade |
| C. | |
| Answer» C. | |
| 407. |
The pole zero plot in the given figure is for |
| A. | non-minimum phase function |
| B. | minimum phase function |
| C. | all pass function |
| D. | either (a) or (b) |
| Answer» D. either (a) or (b) | |
| 408. |
The primary function of lag compensator is to provide sufficient |
| A. | gain margin |
| B. | phase margin |
| C. | both gain margin and phase margin |
| D. | either (a) or (b) |
| Answer» C. both gain margin and phase margin | |
| 409. |
In the given figure, of potentiometer V0 = Vi (R0/Ri) only when |
| A. | RL = 0 |
| B. | RL = ‚àû |
| C. | RL is neither low nor high |
| D. | RL is low but not zero |
| Answer» C. RL is neither low nor high | |
| 410. |
For type 2 system, the magnitude and phase angle of the term (jω)2 in the denominator, at ω = 0, are respectively |
| A. | 0 and - 90° |
| B. | 0 and + 90° |
| C. | infinity and - 180° |
| D. | infinity and + 180° |
| Answer» D. infinity and + 180¬∞ | |
| 411. |
A lag compensator |
| A. | speeds up the transient response of the system |
| B. | improves steady state behaviour of the system |
| C. | improves steady state behaviour and speeds up the transient response of the system |
| D. | improves steady state behaviour and preserves the transient response of the system |
| Answer» E. | |
| 412. |
The static equation of a system is The poles of this system are located at |
| A. | -1, -9 |
| B. | -1, -20 |
| C. | -4, -5 |
| D. | -9, -20 |
| Answer» D. -9, -20 | |
| 413. |
M circles are symmetrical with respect to |
| A. | real and imaginary axis |
| B. | M = 1 straight line and real axis |
| C. | M = 1 straight line and imaginary axis |
| D. | M = 1 straight line |
| Answer» C. M = 1 straight line and imaginary axis | |
| 414. |
In a two phase servomotor the two stator windings have a phase difference of |
| A. | 30° |
| B. | 45° |
| C. | 90° |
| D. | 135° |
| Answer» D. 135¬∞ | |
| 415. |
The compensator of the given figure is a |
| A. | lag compensator |
| B. | lead compensator |
| C. | lag-lead compensator |
| D. | none of the above |
| Answer» C. lag-lead compensator | |
| 416. |
The system matrix of continuous time system described in state variable form isThe systems is stable for all values of x and y satisfying |
| A. | x < 1/2, y < 1/2 |
| B. | x > 1/2, y > 0 |
| C. | x < 0, y < 0 |
| D. | x < 0, y < 1/2 |
| Answer» D. x < 0, y < 1/2 | |
| 417. |
In a second order system, the time constant t of exponential envelopes depends |
| A. | only on damping factor |
| B. | only on natural frequency |
| C. | both on damping factor and natural frequency |
| D. | neither on damping factor nor on natural frequency |
| Answer» D. neither on damping factor nor on natural frequency | |
| 418. |
For the system of the given figure, the damping ratio of closed loop poles is |
| A. | 1.5 |
| B. | 1 |
| C. | 0.5 |
| D. | 0.25 |
| Answer» D. 0.25 | |
| 419. |
The slope of log magnitude curve changes by - 40 dB/decade at a certain frequency and the error between asymptote and actual curve is positive. This means that |
| A. | a double pole is present |
| B. | a pair of complex conjugate poles is present |
| C. | either (a) or (b) |
| D. | neither (a) nor (b) |
| Answer» C. either (a) or (b) | |
| 420. |
In the given figure, the curves 1, 2, 3 are respectively for |
| A. | all pass, minimum phase and non-minimum phase functions |
| B. | minimum phase, all pass and non-minimum phase functions |
| C. | non-minimum phase, all pass and minimum phase functions |
| D. | minimum phase, non-minimum phase and all pass functions |
| Answer» C. non-minimum phase, all pass and minimum phase functions | |
| 421. |
Integral error compensation changes a second order system to |
| A. | first order system |
| B. | third order system |
| C. | fourth order system |
| D. | either (a) or (b) depending on the system |
| Answer» C. fourth order system | |
| 422. |
Consider the following statements about root locus The root locus is symmetrical about real axis.If a root locus branch moves along the real axis from an open loop pole to zero or to infinity, this root locus branch is called real root branch.The breakaway points of the root locus are the solutions of Which statements out of above are correct? |
| A. | 1 and 2 only |
| B. | 1 and 3 only |
| C. | 1, 2 and 3 |
| D. | 2 and 3 only |
| Answer» D. 2 and 3 only | |
| 423. |
Lag compensation permits a high gain at low frequencies. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 424. |
For Bode plot of (1 + jωT) has |
| A. | slope of 20 dB/decade and phase angle + tan-1 (ωT) |
| B. | slope of - 20 dB/decade and phase angle + tan-1 (ωT) |
| C. | slope of 20 dB/decade and phase angle - tan-1 (ωT) |
| D. | slope of - 40 dB/decade and phase angle - tan-1(ωT) |
| Answer» B. slope of - 20 dB/decade and phase angle + tan-1 (œâT) | |
| 425. |
For a second order system delay time td is the time required to reach |
| A. | half the final value for the very first time |
| B. | the final value for the very first time |
| C. | 90% of the final value for the very first time |
| D. | none of the above |
| Answer» B. the final value for the very first time | |
| 426. |
For the system in the given figure G varies slightly, the ratio of open loop sensitivity to closed loop sensitivity is |
| A. | 1 : (1 + GH) |
| B. | 1 : (1 + GH)-1 |
| C. | 1 : (1 - GH) |
| D. | 1 : (1 - GH)-1 |
| Answer» C. 1 : (1 - GH) | |
| 427. |
For a first order system having transfer function , the unit impulse response is |
| A. | e-t/T |
| B. | T e-t/T |
| C. | |
| Answer» D. | |
| 428. |
In the given figure the input frequency f = 10(1/2 p RC) |
| A. | 0 dB |
| B. | 3 dB |
| C. | -3 dB |
| D. | -20 dB |
| Answer» E. | |
| 429. |
Assertion (A): The time response of the system with will not have any overshoot for unit step input.Reason (R): A critically damped system does not have any overshoot to a unit step input. |
| 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 correct but R is wrong |
| D. | R is correct but A is wrong |
| Answer» D. R is correct but A is wrong | |
| 430. |
The polar plot of transport lag is a unit circle. |
| A. | 1 |
| B. | |
| C. | amplifier, demodulator, dc servomotor and load |
| D. | demodulator, amplifier, dc servomotor and load |
| Answer» B. | |
| 431. |
The given figure shows a pole zero diagram. The transfer function G(j1) is |
| A. | 0.5 ∠0 |
| B. | 2.7 ∠- 31° |
| C. | 2 ∠45° |
| D. | 2 ∠- 67.4° |
| Answer» B. 2.7 ‚à†- 31¬∞ | |
| 432. |
Which of the following can be used as a rotating amplifier in a control system? AmplidyneSeparately excited dc generatorSynchroSelf excited dc generator Select the answer from the following codes: |
| A. | 3 and 4 |
| B. | 1 and 2 |
| C. | 1, 2 and 3 |
| D. | all |
| Answer» C. 1, 2 and 3 | |
| 433. |
In the given figure, if R = XC, voltage gain is |
| A. | 0 dB |
| B. | 3 dB |
| C. | -3 dB |
| D. | 20 dB |
| Answer» D. 20 dB | |
| 434. |
As the bandwidth increases, the cost of components |
| A. | generally decreases |
| B. | generally increases |
| C. | may increase or decrease |
| D. | does not change |
| Answer» C. may increase or decrease | |
| 435. |
If the poles lie in second quadrant, damping ratio is |
| A. | 1 |
| B. | less than 1 |
| C. | zero |
| D. | more than 1 |
| Answer» C. zero | |
| 436. |
In control systems the output of sensor usually, is |
| A. | analog electrical signal |
| B. | digital electrical signal |
| C. | mechanical signal |
| D. | analog or digital electrical signal |
| Answer» E. | |
| 437. |
For stable network the real parts of poles and zeros of driving point functions must be |
| A. | negative |
| B. | negative or zero |
| C. | zero |
| D. | positive |
| Answer» C. zero | |
| 438. |
Consider the following statementsThe effect of feedback is to reduce system errorFeedback increases the system gain at one frequency but reduces the system gain as another frequencyFeedback can cause an originally stable system to become unstable Which of the above statements are correct? |
| A. | 1, 2, 3 |
| B. | 1, 2 |
| C. | 2, 3 |
| D. | 1, 3 |
| Answer» E. | |
| 439. |
Assertion (A): The steady state response, of a stable, linear, time invariant system, to sinusoidal input depends on initial conditions. Reason (R): Frequency response, in steady state, is obtained by replacing s in the transfer function by jω |
| 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 correct but R is wrong |
| D. | R is correct but A is wrong |
| Answer» E. | |
| 440. |
The shape of torque-speed curve of a two phase servo- motor mostly depends on |
| A. | ratio of rotor reactance to rotor resistance |
| B. | ratio of stator reactance to rotor resistance |
| C. | ratio of rotor reactance to rotor resistance and also the ratio of stator reactance to stator resistance |
| D. | magnitude of stator voltages |
| Answer» B. ratio of stator reactance to rotor resistance | |
| 441. |
In the given figure, the number of individual loops is |
| A. | 2 |
| B. | 4 |
| C. | 5 |
| D. | 6 |
| Answer» D. 6 | |
| 442. |
The polar plot of |
| A. | does not cross real axis |
| B. | crosses real axis |
| C. | crosses real axis at ω = 0.7 rad/sec |
| D. | crosses real axis at ω = 1.4 rad/sec |
| Answer» B. crosses real axis | |
| 443. |
. It is required that response settles to within 2% of final value for a step input. The settling time is |
| A. | 20 sec |
| B. | 40 sec |
| C. | 35 sec |
| D. | 45 sec |
| Answer» C. 35 sec | |
| 444. |
A negative feedback system has . The closed loop system is stable for |
| A. | K > 20 |
| B. | 15 < K < 19 |
| C. | 8 ≤ K ≤ 14 |
| D. | K < 6 |
| Answer» E. | |
| 445. |
In case of synchro error detector the electrical zero position of control transformer is obtained when angular displacement between rotors is |
| A. | zero |
| B. | 45° |
| C. | 90° |
| D. | 180° |
| Answer» D. 180¬∞ | |
| 446. |
Bode magnitude plot is drawn between |
| A. | magnitude of network function and ω |
| B. | dB magnitude and log ω |
| C. | dB magnitude and ω |
| D. | loge (magnitude) and log ω |
| Answer» C. dB magnitude and œâ | |
| 447. |
For any transfer function, the constant phase angle loci are |
| A. | a family of circles |
| B. | a family of straight lines |
| C. | either (a) or (b) |
| D. | neither (a) nor (b) |
| Answer» B. a family of straight lines | |
| 448. |
For the given figure, time constant RC = t. Then |
| A. | t2s2 + 2ts + 1 |
| B. | |
| Answer» C. | |
| 449. |
The phase angle curve of G(jω) H(jω) can be drawn |
| A. | by adding the phase angle curves of individual factors |
| B. | by subtracting the phase angle curves of individual factors |
| C. | by multiplying the phase angle curves of individual factors |
| D. | by dividing the phase angle curves of individual factors |
| Answer» B. by subtracting the phase angle curves of individual factors | |
| 450. |
Assertion (A): Positive feedback is not used in any circuit.Reason (R): Positive feedback leads to instability. |
| 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 correct but R is wrong |
| D. | R is correct but A is wrong |
| Answer» E. | |