MCQOPTIONS
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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.
| 251. |
In Bode plots the frequency at which two asymptotes meet is called corner frequency. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 252. |
Gain margin and phase margin can be determined from Bode plots as well as Nyquist plot. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 253. |
If zeros at infinity are included in the count, the number of zeros of G(s) H(s) is |
| A. | equal to number of poles |
| B. | one more than the number of poles |
| C. | one less than the number of poles |
| D. | none of the above |
| Answer» B. one more than the number of poles | |
| 254. |
Assertion (A): Increasing the system gain improves steady state behaviour but may result in instability.Reason (R): A compensator is inserted into a system to ensure specified performance. |
| 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» C. A is correct but R is wrong | |
| 255. |
Robotic manipulator arms mostly use |
| A. | hydraulic actuator |
| B. | pneumatic actuator |
| C. | electric motor actuator |
| D. | none of the above |
| Answer» D. none of the above | |
| 256. |
The current rating of dc tachogenerator is usually |
| A. | small |
| B. | high |
| C. | medium |
| D. | either (b) or (c) |
| Answer» B. high | |
| 257. |
A system is highly oscillatory if |
| A. | gain margin is high |
| B. | gain margin is close to 1 |
| C. | gain margin is close to 1 or phase margin is zero |
| D. | gain margin is high and phase margin is 180° |
| Answer» D. gain margin is high and phase margin is 180¬∞ | |
| 258. |
Gas flow resistance is defined as |
| A. | |
| B. | |
| Answer» B. | |
| 259. |
Assertion (A): In simplifying block diagram the product of transfer functions in feed forward direction must remain the same.Reason (R): In simplifying block diagram the product of transfer functions around a closed loop must remain the same. |
| 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» C. A is correct but R is wrong | |
| 260. |
In the given figure the input frequency f = 0.1 (1/2 p RC) |
| A. | 0 dB |
| B. | 3 dB |
| C. | -3 dB |
| D. | 20 dB |
| Answer» B. 3 dB | |
| 261. |
For the system with , the maximum resonance peak is |
| A. | 4 |
| B. | 43528 |
| C. | 2 |
| D. | 43526 |
| Answer» E. | |
| 262. |
Assertion (A): Points in the s plane at which function G(s) is not analytic are called singular, points.Reason (R): Singular points at which the function G(s) or its derivative approach infinity are called poles. |
| 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» C. A is correct but R is wrong | |
| 263. |
For the system of the given figure, the closed loop poles are at |
| A. | 0 and -4 |
| B. | -2 ± j6 |
| C. | 2 ± j6 |
| D. | -3 ± j8 |
| Answer» C. 2 ¬± j6 | |
| 264. |
Accurate amplitude measurements can be made more easily than accurate phase shift measurements. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 265. |
Examine the following statements Pneumatic systems are fire proof.Pneumatic systems are explosion proof.Hydraulic systems are explosion proof.Hydraulic systems are fire proof. Which of the above statements are correct? |
| A. | 1 only |
| B. | 1 and 2 only |
| C. | 1 2, 3, 4 |
| D. | 2, 3, 4 only |
| Answer» C. 1 2, 3, 4 | |
| 266. |
Assertion (A): If minimum phase system has a gain margin of 8 dB and phase margin of 21°, the system is stable.Reason (R): For a minimum phase system both GM and PM must be positive for the system to be stable. |
| 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 | |
| 267. |
The distance of poles from origin depends on |
| A. | undamped natural frequency |
| B. | damping ratio |
| C. | both (a) and (b) |
| D. | neither (a) nor (b) |
| Answer» B. damping ratio | |
| 268. |
Temperature is analogous to |
| A. | voltage |
| B. | flux |
| C. | charge |
| D. | none of the above |
| Answer» B. flux | |
| 269. |
For a factor the log |
| A. | is a straight line with slope 20 dB/decade |
| B. | is a straight line with slope 0 dB/decade |
| C. | is a straight line with slope - 20 dB/decade |
| D. | is a straight line with slope - 40 dB/decade |
| Answer» E. | |
| 270. |
Consider the following statements:The gain margin and phase margin of an unstable system may respectively be positive, positivepositive, negativenegative, positivenegative, negative Of these statements |
| A. | 1, 4 are correct |
| B. | 1 and 2 correct |
| C. | 1, 2, 3 are correct |
| D. | 2, 3, 4 are correct |
| Answer» E. | |
| 271. |
Assertion (A): The root locus of a control system is symmetrical about real axis.Reason (R): For all polynomials with real coefficients, complex poles always occur in conjugate pairs. |
| 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 | |
| 272. |
Transport lag usually exists in |
| A. | thermal systems |
| B. | hydraulic systems and thermal systems |
| C. | pneumatic systems |
| D. | thermal, hydraulic and pneumatic systems |
| Answer» E. | |
| 273. |
If any term in the first column of a Routh array becomes zero, then |
| A. | Routh criterion cannot be used to determine stability |
| B. | Routh criterion can be used by substituting a small positive number for zero and completing the array |
| C. | Routh criterion can be used by substituting a big positive number for zero and completing the array |
| D. | Routh criterion can be used by substituting a small negative number for zero and completing the array |
| Answer» C. Routh criterion can be used by substituting a big positive number for zero and completing the array | |
| 274. |
The loop transfer function of a feedback system is . The number of asymptotes of its root loci are |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» E. | |
| 275. |
In a lag network the input frequency is 100 fc where fc is critical frequency. The voltage gain is |
| A. | 0 dB |
| B. | -20 dB |
| C. | -40 dB |
| D. | -60 dB |
| Answer» D. -60 dB | |
| 276. |
A second order system exhibits 100% overshoot. The damping ratio is |
| A. | 0 |
| B. | 1 |
| C. | < 1 |
| D. | > 1 |
| Answer» B. 1 | |
| 277. |
In control systems the magnitude of error voltage |
| A. | is very small |
| B. | is very large |
| C. | neither small nor large |
| D. | may be any value from 0 to 50 V |
| Answer» B. is very large | |
| 278. |
For a first order system having transfer function , the unit ramp response is |
| A. | T(1 - e-t/T) |
| B. | t - T + T e-t/T |
| C. | t + T + T e-t/T |
| D. | t + 2T e-t/T |
| Answer» C. t + T + T e-t/T | |
| 279. |
An electromechanical device which actuates a train of step angular movements in response to a train of input pulses on one to one basis is |
| A. | synchro control transformer |
| B. | LVDT |
| C. | stepper motor |
| D. | tacho generator |
| Answer» D. tacho generator | |
| 280. |
In a second order system with a unit step input, the speed of response is high if system is |
| A. | overdamped |
| B. | undamped system |
| C. | critically damped |
| D. | underdamped |
| Answer» E. | |
| 281. |
An open loop system has a forward path transfer function (42.25)/s(s + 6.5). The unit step response of the system starting from rest will have its maximum value at a time equal to |
| A. | 0 sec |
| B. | 0.56 sec |
| C. | 5.6 sec |
| D. | infinity |
| Answer» E. | |
| 282. |
The transfer function has the characteristics of high pass filter. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 283. |
Bandwidth is proportional to speed of response. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 284. |
Assertion (A): The transient performance of a control system is generally analysed by using unit step function as reference input.Reason (R): Impulse is the most common input found in practice. |
| 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 | |
| 285. |
In a synchro transmitter, which coil acts as primary? |
| A. | Rotor |
| B. | Stator |
| C. | Partly rotor and partly stator |
| D. | Tertiary |
| Answer» B. Stator | |
| 286. |
In force voltage analogy the quantity analogous to spring constant K is |
| A. | R |
| B. | C |
| C. | L |
| D. | 1/C |
| Answer» E. | |
| 287. |
Nyquist plot provides information about absolute stability as well as relative stability. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 288. |
Which of the following can act as error detecting devices a pair of potentiometersa pair of synchrosa differential transformera metadynea control transformer Select the answer using the following codes: |
| A. | 1, 2, 5 |
| B. | 2, 3, 4, 5 |
| C. | 1, 3, 4, 5 |
| D. | 1, 2, 3, 4 |
| Answer» B. 2, 3, 4, 5 | |
| 289. |
A conditionally stable system is stable for the value of gain between two critical values. It is unstable if |
| A. | the gain is increased beyond upper critical value |
| B. | the gain is decreased below lower critical value |
| C. | both (a) and (b) |
| D. | none of the above |
| Answer» D. none of the above | |
| 290. |
For any test point s on the real axis, the sum of angular contributions of the complex conjugate poles is |
| A. | 90° |
| B. | 180° |
| C. | 270° |
| D. | 360° |
| Answer» E. | |
| 291. |
The response is |
| A. | undamped |
| B. | underdamped |
| C. | critically damped |
| D. | oscillatory |
| Answer» C. critically damped | |
| 292. |
A unity feedback system has . If input r(t) = 1 + 2t + t3, the steady error is |
| A. | zero |
| B. | 0.4 |
| C. | 4 |
| D. | infinity |
| Answer» E. | |
| 293. |
The slope of log-magnitude asymptote changes by - 40 dB/ decade at a frequency ω1. This means that |
| A. | a double pole is present |
| B. | a pair of complex conjugate poles is present |
| C. | either a double pole or a pair of complex conjugate poles is present |
| D. | a pole or zero at origin is present |
| Answer» D. a pole or zero at origin is present | |
| 294. |
If the polar plot, as the frequency is varied from 0 to infinity is |
| A. | a semicircle |
| B. | a circle |
| C. | a straight line |
| D. | none of the above |
| Answer» B. a circle | |
| 295. |
In a proportional plus integral control action |
| A. | proportional gain Kp is adjustable but integral time Ti is constant |
| B. | proportional gain Kp is adjustable but integral time Ti is adjustable |
| C. | both proportional gain Kp and integral time Ti are adjustable |
| D. | both proportional gain Kp and integral time Ti are constant |
| Answer» D. both proportional gain Kp and integral time Ti are constant | |
| 296. |
The correct sequence of events to improve system stability is |
| A. | insert derivative action, use negative feedback, reduce gain |
| B. | reduce gain, use negative feedback, insert derivative action |
| C. | reduce gain, insert derivative feedback, use negative feed back |
| D. | use negative feedback, reduce gain, insert derivative action |
| Answer» E. | |
| 297. |
In Bode diagrams an octave is a frequency band from |
| A. | ω1 to 10 ω1 |
| B. | ω1 to 8 ω1 |
| C. | ω1 to 4 ω1 |
| D. | ω1 to 2 ω1 |
| Answer» E. | |
| 298. |
For an m x n matrix A, the eigen values are the roots of the characteristic equation |
| A. | |I - A| |
| B. | |λI - A| = 0 |
| C. | |λA - I| = 0 |
| D. | |A - I| = 0 |
| Answer» C. |ŒªA - I| = 0 | |
| 299. |
For a second order system the damping factor is varied from 0 to 1. The locus of poles is |
| A. | a straight line on imaginary axis |
| B. | a straight line on real axis |
| C. | a semi circle |
| D. | a circle |
| Answer» D. a circle | |
| 300. |
The log magnitude plot of the given figure is for |
| A. | type 0 system |
| B. | type 1 system |
| C. | type 2 system |
| D. | either type 0 or type 1 system |
| Answer» B. type 1 system | |