MCQOPTIONS
Saved Bookmarks
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.
| 201. |
The purpose of series quadrature windings in amplidyne is to |
| A. | neutralize the effect of armature reaction |
| B. | reduce commutation difficulties |
| C. | increase the gain |
| D. | increase response time |
| Answer» B. reduce commutation difficulties | |
| 202. |
One advantage of using polar plot is that it depicts the frequency response characteristics over the entire frequency. |
| A. | coulomb friction |
| B. | viscous friction |
| C. | static friction |
| D. | none of the above |
| Answer» B. viscous friction | |
| 203. |
Assertion (A): The phase angle plot in Bode diagram is not affected by change in system gain.Reason (R): The variation in gain has no effect on phase margin of the system. |
| 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 | |
| 204. |
The open loop transfer function of a unity feedback system is The poles of closed loop system are at |
| A. | -2, -2 |
| B. | -2, -1 |
| C. | - 2, ± j 1 |
| D. | - 2, 2 |
| Answer» D. - 2, 2 | |
| 205. |
In a mechanical accelerometer, the steady state displacement is a measure of |
| A. | constant input acceleration |
| B. | constant input velocity |
| C. | either (a) or (b) |
| D. | neither (a) nor (b) |
| Answer» B. constant input velocity | |
| 206. |
Assertion (A): When a PID controller is added to a system, the peak overshoot to step input cannot be determined easily.Reason (R): Use of PID controller introduces a zero in the forward path. |
| 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 | |
| 207. |
Assertion (A): In root locus the breakaway and break in points either lie on real axis or occur in complex conjugate pairs.Reason (R): All root locus asymptotes intersect on real axis. |
| A. | A is correct but R is wrong |
| B. | R is correct but A is wrong |
| C. | Both A and R are correct and R is correct explanation of A |
| D. | Both A and R are correct but R is not correct explanation of A |
| Answer» C. Both A and R are correct and R is correct explanation of A | |
| 208. |
The compensator in the given figure is a |
| A. | lag compensator |
| B. | lead compensator |
| C. | lag-lead compensator |
| D. | none of the above |
| Answer» D. none of the above | |
| 209. |
For the factor the corner frequency is |
| A. | 0.5 rad/sec |
| B. | 1 rad/sec |
| C. | 2 rad/sec |
| D. | 4 rad/sec |
| Answer» B. 1 rad/sec | |
| 210. |
The addition of a pole to the open loop transfer function pulls the root locus |
| A. | to the right |
| B. | to the left and making the system more stable |
| C. | towards right or left depending on the position of new pole |
| D. | none of the above |
| Answer» B. to the left and making the system more stable | |
| 211. |
Coulomb friction is |
| A. | the force of sliding friction between dry surfaces |
| B. | the force of friction between moving surfaces separated by viscous fluid |
| C. | the force required to initiate motion between two contacting surfaces |
| D. | all of the above |
| Answer» B. the force of friction between moving surfaces separated by viscous fluid | |
| 212. |
The M circle for M = 1 is the |
| A. | straight line at x = - 0.5 |
| B. | critical point (-l, jo) |
| C. | circle with r = 0.33 |
| D. | circle with r = 0.67 |
| Answer» B. critical point (-l, jo) | |
| 213. |
For the second order system damping ratio is |
| A. | 0.1 |
| B. | 0.25 |
| C. | 0.333 |
| D. | 0.5 |
| Answer» E. | |
| 214. |
In the given figure shows a root locus plot. Consider the following statements for this plot The open loop system is a second order systemThe system is overdamped for K > 1The system is stable for all values of K Which of the above statements are correct? |
| A. | 1, 2, 3 |
| B. | 1, 3 |
| C. | 2, 3 |
| D. | 1, 2 |
| Answer» C. 2, 3 | |
| 215. |
The given figure shows a hybrid servosystem. The components 1, 2, 3, 4 are respectively |
| A. | demodulator, dc servomotor, amplifier and load |
| B. | amplifier, dc servomotor, demodulator and load |
| C. | 1, 2, 3 |
| D. | 1, 2 |
| Answer» B. amplifier, dc servomotor, demodulator and load | |
| 216. |
A lead compensator |
| A. | speeds up the transient response |
| B. | increases the stability margin |
| C. | increases the stability margin and speeds up the transient-response. |
| D. | none of the above. |
| Answer» D. none of the above. | |
| 217. |
Magnetic amplifier is used for |
| A. | voltage amplification |
| B. | power amplification |
| C. | current amplification |
| D. | frequency amplification |
| Answer» C. current amplification | |
| 218. |
A compensating network has . If it is a phase lag circuit the value of a should be |
| A. | 0 |
| B. | between 0 and 1 |
| C. | 1 |
| D. | more than 1 |
| Answer» C. 1 | |
| 219. |
In a second order undamped system, the poles are on |
| A. | positive real axis |
| B. | imaginary axis |
| C. | negative real axis |
| D. | either (a) or (c) |
| Answer» C. negative real axis | |
| 220. |
For as ω approaches infinity, the magnitude approaches zero and phase angle approaches - 90°. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 221. |
In an armature controlled dc motor let J be equivalent moment of inertia of motor and load, f0 be equivalent viscous friction coefficient of motor and load and θ be angular displacement of motor shaft. Then torque equation is |
| A. | |
| B. | |
| Answer» B. | |
| 222. |
In force current analogue, mechanical mobility is analogous to |
| A. | impedance Z |
| B. | admittance Y |
| C. | reactance X |
| D. | conductance G |
| Answer» B. admittance Y | |
| 223. |
When time constant T in any factor is varied, the shapes of log magnitude and phase angle curves remain the same. |
| A. | 1 |
| B. | |
| C. | Rotor diameter is small |
| D. | Applied voltages are seldom balanced |
| Answer» B. | |
| 224. |
Consider the following statements about transport-lag It is of non-minimum phase behaviourIt normally exists in thermal, hydraulic and pneumatic systemsIt has an excessive phase lag with no attenuation at high frequency Which of the above statements are correct? |
| A. | 1 only |
| B. | 1 and 2 |
| C. | All |
| D. | 2 and 3 |
| Answer» D. 2 and 3 | |
| 225. |
For the characteristic equation s5 + s4 + 2s3 + 2s2 + 3s + 15 = 0, the number of roots in left half s plane are |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 5 |
| Answer» D. 5 | |
| 226. |
At corner frequency the phase angle of factor is - 45° |
| A. | 1 |
| B. | |
| Answer» B. | |
| 227. |
If feedback factor is β the overall gain of a closed loop system is approximately equal to |
| A. | |
| B. | |
| Answer» C. | |
| 228. |
Which dc servomotor has minimum inertia? |
| A. | Slotted armature construction |
| B. | Surface wound armature |
| C. | Surface wound with stationary rotor |
| D. | Either (a) or (b) |
| Answer» D. Either (a) or (b) | |
| 229. |
If , the number of branches of root locus are |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» E. | |
| 230. |
For a closed loop systemThe imaginary axis intercept of the root loci will be |
| A. | ± j 2.8 |
| B. | ± J 0.28 |
| C. | ± j 1.14 |
| D. | ± j 11.4 |
| Answer» B. ¬± J 0.28 | |
| 231. |
Assertion (A): A large negative feedback is deliberately introduced in an amplifier to make its gain independent of variation in parameters of active device.Reason (R): A large negative value of feedback results in a high value of return difference compared to unity which makes the feedback gain inversely proportional to the feedback factor. |
| 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 | |
| 232. |
The root locus branches |
| A. | start from open loop poles and terminate at zeros |
| B. | start from open loop zeros and terminate at poles |
| C. | may start from pole or zero and terminate at another pole or zero |
| D. | none of the above |
| Answer» B. start from open loop zeros and terminate at poles | |
| 233. |
The maximum shift which can be provided by a lead compensator with transfer function is |
| A. | 15° |
| B. | 30° |
| C. | 45° |
| D. | 60° |
| Answer» C. 45¬∞ | |
| 234. |
For a quadratic factor in transfer function the phase angle is not a function of damping factor. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 235. |
For the system in the given figure, the gain margin is |
| A. | 0 |
| B. | low |
| C. | + ‚àû |
| D. | none of the above |
| Answer» D. none of the above | |
| 236. |
In a pneumatic bellows |
| A. | the input surface, output surface and side walls are corrugated |
| B. | the input surface and output surface are flat but the side walls are corrugated |
| C. | the input surface and side walls are flat but the output surface is corrugated |
| D. | the input surface and output surface are corrugated but the side walls are flat |
| Answer» C. the input surface and side walls are flat but the output surface is corrugated | |
| 237. |
In classical analogue, torque is analogous to |
| A. | current |
| B. | voltage |
| C. | charge |
| D. | voltage gradient |
| Answer» C. charge | |
| 238. |
A synchro transmitter receiver unit is a |
| A. | two phase ac device |
| B. | 3 phase ac device |
| C. | dc device |
| D. | 1 phase ac device |
| Answer» E. | |
| 239. |
The log magnitude curve of factor jω is a straight line having a slope of 20 dB/decade. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 240. |
For a stable system having two or more gain crossover frequencies the phase margin is measured |
| A. | at lowest gain crossover frequency |
| B. | at highest gain crossover frequency |
| C. | at the gain crossover frequencies |
| D. | none of the above |
| Answer» C. at the gain crossover frequencies | |
| 241. |
The number of stator field windings in an ac tachometer are |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 242. |
For the transfer function , the polar plot a is |
| A. | semi circle |
| B. | circle |
| C. | spiral |
| D. | none of the above |
| Answer» D. none of the above | |
| 243. |
In log magnitude Bode diagram the slope of high frequency asymptote of (1 + jωT) is |
| A. | 20 dB per decade |
| B. | 10 dB per decade |
| C. | 20 dB per octave |
| D. | 10 dB per octave |
| Answer» B. 10 dB per decade | |
| 244. |
The poles with greater displacement from the real axis correspond to |
| A. | higher frequencies of oscillations |
| B. | stable response |
| C. | lower frequencies of oscillations |
| D. | unbounded output |
| Answer» B. stable response | |
| 245. |
Assertion (A): Temperature control of the passenger compartment of car uses both feed forward and feedback controls.Reason (R): Feed forward control gives corrective action before the disturbance affects the output and feedback control applies corrective action after output changes. |
| 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 | |
| 246. |
Friction forces acts in a direction |
| A. | opposite to that of velocity |
| B. | same as that of velocity |
| C. | at right angle to that of velocity |
| D. | partly opposite and partly at right angle to the direction of velocity |
| Answer» B. same as that of velocity | |
| 247. |
N circles for a = a1, and a = a1 ± 180° n (where n = 1, 2, 3, ....) are the same. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 248. |
In a simple on-off controller with differential gap, the magnitude of differential gap determines |
| A. | the level of accuracy |
| B. | the life of controller |
| C. | both (a) and (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 249. |
Assertion (A): A synchro control transformer has nearly constant impedance across its rotor terminals.Reason (R): Rotor of a synchro control transformer is cylindrical so as to give uniform flux distribution. |
| 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 | |
| 250. |
For the system of the given figure the closed loop poles are located at |
| A. | s = 0 and s = -2 |
| B. | s = 0, s = -l ± j3 |
| C. | s = -1 ± j3 |
| D. | s = -2 and s = -1 ± j3 |
| Answer» D. s = -2 and s = -1 ¬± j3 | |