57.

58.

59.

60.

61.

62.

The polynomial A(S)= S* +3S° +2S +6 has:
(A) Two roots in left half of S-plane and one root in right half
(B) Two roots in right half of S-plane and one root in left half
(C) Two roots on j @-axis of S-plane and one root in right half

(D) Two roots on j @-axis of S-plane and one root in left half

1
joll+ jot)

(A) Crosses the negative real axis

Polar plot of G(ja)=

(B) Crosses the negative imaginary axis
(C) Crosses the positive imaginary axis
(D) None of the answers in the (A), (B) and (C) is correct

In control systems
@ Reduction in bandwidth results in sluggish response
Gi) Reduction in bandwidth results in better signal/noise ratio
Which of the following is correct answer?
(A) None of the above statements is true
(B) Statement (i) is true but statement (ii) is false
(C) Statement (ii) is true but statement (i) is false
(D) Both Statements are true
Occasionally in applying the Routh stability criterion, certain difficulties arise causing the

breakdown of Routh test. One of the difficulties is given as follows. “When all elements in any
one row of the Routh array are zero”. This condition is indicating:

(A) Symmetrically located roots in the Complex plane
(2) Unsymmetrically located roots in the complex plane
(C) Roots located in the left half of the S-plane only
(D) Roots located in the right half of the S-plane only
The holding current of an SCR is 20 mA. The latching current will be:
(A) 20 ‏۸ھ‎ (B) 200 mA
(C) 22 mA (D) 18mA
A line commutated single phase fully controlled rectifier operates as an inverter at firing
angles:
(ಗ) 90° (൮ 050590 ൯) 050590

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