Polar Nyquist Plots - Electronic Engineering (MCQ) questions & answers

1)   If a Nyquist plot of G (jω) H (jω) for a closed loop system passes through (-2, j0) point in GH plane, what would be the value of gain margin of the system in dB?

a. 0 dB
b. 2.0201 dB
c. 4 dB
d. 6.0205 dB
Answer  Explanation 

ANSWER: 6.0205 dB

Explanation:
No explanation is available for this question!


2)   Consider the system represented by the equation given below. What would be the total phase value at ω = 0?
200/ [s3 (s + 3) (s + 6) (s + 10)]


a. -90°
b. -180°
c. -270°
d. -360°
Answer  Explanation 

ANSWER: -270°

Explanation:
No explanation is available for this question!


3)   Consider a feedback system with gain margin of about 30. At what point does Nyquist plot crosses negative real axis?

a. -3
b. -0.3
c. -30
d. -0.03
Answer  Explanation 

ANSWER: -0.3

Explanation:
No explanation is available for this question!


4)   Which principle specifies the relationship between enclosure of poles & zeros by s-plane contour and the encirclement of origin by q(s) plane contour?

a. Argument
b. Agreement
c. Assessment
d. Assortment
Answer  Explanation 

ANSWER: Argument

Explanation:
No explanation is available for this question!


5)   For Nyquist contour, the size of radius is _______

a. 25
b. 0
c. 1
d.
Answer  Explanation 

ANSWER: ∞

Explanation:
No explanation is available for this question!


6)   According to Nyquist stability criterion, where should be the position of all zeros of q(s) corresponding to s-plane?

a. On left half
b. At the center
c. On right half
d. Random
Answer  Explanation 

ANSWER: On left half

Explanation:
No explanation is available for this question!


7)   If the system is represented by G(s) H(s) = k (s+7) / s (s +3) (s + 2), what would be its magnitude at ω = ∞?

a. 0
b.
c. 7/10
d. 21
Answer  Explanation 

ANSWER: 0

Explanation:
No explanation is available for this question!


8)   Due to an addition of pole at origin, the polar plot gets shifted by  ___ at ω = 0?

a. -45°
b. -60°
c. -90°
d. -180°
Answer  Explanation 

ANSWER: -90°

Explanation:
No explanation is available for this question!


9)   In polar plots, if a pole is added at the origin, what would be the value of the magnitude at Ω = 0?

a. Zero
b. Infinity
c. Unity
d. Unpredictable
Answer  Explanation 

ANSWER: Infinity

Explanation:
No explanation is available for this question!


10)   In polar plots, what does each and every point represent w.r.t magnitude and angle?

a. Scalar
b. Vector
c. Phasor
d. Differentiator
Answer  Explanation 

ANSWER: Phasor

Explanation:
No explanation is available for this question!