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.
| 301. |
In force voltage analogy, displacement is analogous to |
| A. | current |
| B. | voltage |
| C. | charge |
| D. | none of the above |
| Answer» D. none of the above | |
| 302. |
The log magnitude curve for a constant gain K is a horizontal straight line at a magnitude 20 log K dB. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 303. |
A conditionally stable system has |
| A. | one phase crossover frequency |
| B. | two phase crossover frequencies |
| C. | two or more phase crossover frequencies |
| D. | one or more phase crossover frequencies |
| Answer» D. one or more phase crossover frequencies | |
| 304. |
An ac tachometer has a drag cup construction so that |
| A. | rotor inertia is low |
| B. | rotor body is conducting |
| C. | rotor is easy to fabricate |
| D. | both (a) and (b) |
| Answer» E. | |
| 305. |
Assertion (A): If integral control action is included in the controller the offset can be eliminated.Reason (R): Integral control action may lead to oscillatory response. |
| 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 | |
| 306. |
For the transport lag G(jω) = e-jωT, the polar plot is |
| A. | a semi circle |
| B. | a circle |
| C. | a unit circle |
| D. | none of the above |
| Answer» D. none of the above | |
| 307. |
DC servomotors are, generally |
| A. | permanent magnet dc motors |
| B. | shunt field motors |
| C. | separately excited dc motors |
| D. | none of the above |
| Answer» B. shunt field motors | |
| 308. |
At corner frequency the phase angle of factor 1/(1 + jωT) is |
| A. | +90° |
| B. | -90° |
| C. | +45° |
| D. | -45° |
| Answer» E. | |
| 309. |
In the signal flow graph of the given figure, the number of forward paths is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 310. |
Assertion (A): For an underdamped system with damping ratio ξ, the maximum overshoot is e-ξp/(1-ξ2)0.5Reason (R): Peak time of a second order under damped system = p/ωd where ωd is frequency of damped oscillations. |
| 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 | |
| 311. |
The force required to initiate motion between two contacting surfaces is called |
| A. | coulomb friction |
| B. | viscous friction |
| C. | static friction |
| D. | none of the above |
| Answer» D. none of the above | |
| 312. |
The polar plot of is the negative imaginary axis. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 313. |
M circles are symmetrical with respect to real axis. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 314. |
The action of bellows is similar to that of |
| A. | mass |
| B. | viscous friction |
| C. | spring |
| D. | none of the above |
| Answer» D. none of the above | |
| 315. |
In some on-off controllers a differential gap is provided |
| A. | to make the manufacture process easier |
| B. | to prevent too often frequent operation of controller |
| C. | both (a) and (b) |
| D. | neither (a) nor (b) |
| Answer» C. both (a) and (b) | |
| 316. |
Assertion (A): Nyquist stability criterion uses the number of encirclements around (-1 + j0) point in GH plane to determine stabilityReason (R): The (-1 + j0) point in the s plane lies in the Nyquist 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» D. R is correct but A is wrong | |
| 317. |
The addition of a zero to the open loop transfer function |
| A. | pulls the root locus to the left and makes the system more stable |
| B. | pulls the root locus to the right and makes the system less stable |
| C. | either (a) or (b) |
| D. | neither (a) nor (b) |
| Answer» B. pulls the root locus to the right and makes the system less stable | |
| 318. |
For low frequencies such that , the log magnitude of factor is 0 dB. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 319. |
If G(s)H(s) = K (T1s + 1)/[s2 (T2s + 1)] the system stability depended an relative magnitudes of T1 and T2. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 320. |
Power handling capacity of wire wound potentiometer used in control systems is about |
| A. | 0.1 W |
| B. | 5 W |
| C. | 25 W |
| D. | 100 W |
| Answer» C. 25 W | |
| 321. |
The overall transfer function for a unity feedback system is . Which of the following statements about this system are correct? Position error constant Kp is 4System is type 1Velocity error constant is finite Select the answer as per following code: |
| A. | 1, 2, 3 |
| B. | 1, 2 |
| C. | 2, 3 |
| D. | 1, 3 |
| Answer» E. | |
| 322. |
The number of branches of root locus plot is equal to |
| A. | the number of roots of characteristic equation |
| B. | double the number of roots of characteristic equation |
| C. | the number of roots of characteristic equation minus one |
| D. | the number of roots of characteristic equation plus one |
| Answer» B. double the number of roots of characteristic equation | |
| 323. |
Which of the following are applications of position control systems? |
| A. | Control of sheet and metal thickness in hot rolling mill |
| B. | Missile guidance of ships |
| C. | Radar tracking system |
| D. | All of the above |
| Answer» E. | |
| 324. |
Assertion (A): A slight change in pole-zero configuration can cause only minor changes in root locus configuration.Reason (R): Asymptotes show the behaviour of root loci for |s| >> 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» E. | |
| 325. |
A system has high gain and phase margin. The system is |
| A. | very stable |
| B. | sluggish |
| C. | very stable and sluggish |
| D. | oscillatory |
| Answer» D. oscillatory | |
| 326. |
Assertion (A): In the given figure open loop transfer function = Reason (R): The ratio is called feed forward transfer function. |
| 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 | |
| 327. |
Which of the following is not a necessary advantage of negative feedback system? |
| A. | Feedback improves speed of response |
| B. | Feedback improves stability |
| C. | Feedback reduces effect of variations in system parameters |
| D. | Feedback reduces the effect of external disturbances |
| Answer» C. Feedback reduces effect of variations in system parameters | |
| 328. |
Derivative control action is effective? |
| A. | Only during steady state periods |
| B. | Only during transient state periods |
| C. | During both steady state and transient state periods |
| D. | Either during steady state or during transient state periods |
| Answer» C. During both steady state and transient state periods | |
| 329. |
The phase difference (jω - p1) means |
| A. | phasor drawn from p1 to jω |
| B. | phasor drawn from origin to p1 |
| C. | phasor directed from origin to jω point |
| D. | phasor directed from jω to p1 |
| Answer» B. phasor drawn from origin to p1 | |
| 330. |
The system of the given figure |
| A. | is unstable for all values of K |
| B. | is stable for all values of K |
| C. | can be stable for some values of K |
| D. | data is insufficient to determine stability |
| Answer» B. is stable for all values of K | |
| 331. |
For the block diagram of the given figure, the equation describing system dynamics is |
| A. | (1 + RCs) Δθ0(s) = Δθi(s) + R Δ H(s) |
| B. | (1 + RCs) [ΔH(s)] = Δθ(s) - Δθ0(s) |
| C. | (1 + RCs) Δθ0(s) = RΔ H(s) - Δ θi(s) |
| D. | (1 + RCs) Δθi(s) = Δ H(s)[R] - Δθ0(s) |
| Answer» B. (1 + RCs) [ŒîH(s)] = ŒîŒ∏(s) - ŒîŒ∏0(s) | |
| 332. |
For underdamped second order systems the rise time is the time required for the response to rise from |
| A. | 0% to 100% of its final value |
| B. | 10% to 90% of its final value |
| C. | 5% to 95% of its final value |
| D. | either (a) or (b) |
| Answer» B. 10% to 90% of its final value | |
| 333. |
Nichol's chart is symmetric about - 180° axis. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 334. |
For a factor in the transfer function, the log magnitude plot |
| A. | is a straight line with slope 0 dB/decade |
| B. | is a straight line with slope 20 dB/decade |
| C. | is a straight line with slope - 20 dB/decade |
| D. | is a straight line with slope - 40 dB/decade |
| Answer» E. | |
| 335. |
For a stable system having two or more gain crossover frequencies the phase margin is measured at the highest crossover frequency. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 336. |
A thermometer requires 1 minute to indicate 98% of its final response to a step input. If it is a first order system the time constant is |
| A. | 1 minute |
| B. | 0.5 minute |
| C. | 0.25 minute |
| D. | 0.1 minute |
| Answer» D. 0.1 minute | |
| 337. |
A system hasFor unit step input the settling time for 2% tolerance band is |
| A. | 1.6 |
| B. | 2.5 |
| C. | 4 |
| D. | 5 |
| Answer» E. | |
| 338. |
The network of the given figure is a |
| A. | lag network |
| B. | lead network |
| C. | lag-lead network |
| D. | any of the above |
| Answer» C. lag-lead network | |
| 339. |
For a type 1 system and unit parabolic input, the steady state error is |
| A. | 0 |
| B. | ‚àû |
| C. | 1 |
| D. | 1/Kv |
| Answer» C. 1 | |
| 340. |
The functions and have |
| A. | identical magnitude and phase curves |
| B. | identical magnitude curves but different phase curves |
| C. | different magnitude curves but identical phase curves |
| D. | different magnitude and phase curves |
| Answer» C. different magnitude curves but identical phase curves | |
| 341. |
Assertion (A): Inverse Laplace transform can be found from P(s) by inversion integral.Reason (R): The function f(t) is assumed to be zero for t < 0. |
| 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 | |
| 342. |
For a second order system, the position of poles is in the shaded region shown in the given figure. The variation in damping factor is |
| A. | from 0 to 1 |
| B. | from about 0.3 to 0.7 |
| C. | from 1 to 5 |
| D. | from 0 to 3 |
| Answer» C. from 1 to 5 | |
| 343. |
If block diagrams of the given figure (a) and (b) are to be equivalent, then |
| A. | G2 = G1 |
| B. | |
| Answer» C. | |
| 344. |
For a first order system having transfer function, the unit step response is |
| A. | 1 - e-t/T |
| B. | e-t/T |
| C. | #NAME? |
| D. | 1 + e-t/T |
| Answer» B. e-t/T | |
| 345. |
If , the closed loop pole will be located at s = -12 when K = |
| A. | 4355 |
| B. | 5760 |
| C. | 9600 |
| D. | 9862 |
| Answer» C. 9600 | |
| 346. |
Polar plot of a lag-lead compensator is a circle. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 347. |
Assertion (A): The closeness of G(jω) locus to (- 1 + j0) point can be used as a measured of margin of stability.Reason (R): When the G(jω) locus comes close to encircling (- 1 + j0) point the system becomes oscillatory. |
| 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 | |
| 348. |
A first-order system has a time constant t. For unit ramp input, the steady state error is |
| A. | t2 |
| B. | t |
| C. | t |
| D. | 1/t |
| Answer» C. t | |
| 349. |
For the factor (1 + 0.5 jω) the corner frequency is |
| A. | 1 rad/sec |
| B. | 0.5 rad/sec |
| C. | 2 rad/sec |
| D. | 0.25 rad/sec |
| Answer» D. 0.25 rad/sec | |
| 350. |
In Bode method of stability analysis, the error curve is not symmetric about corner frequency. |
| A. | 1 |
| B. | |
| Answer» C. | |