Engineering Quantitative Aptitude English Reasoning General Knowledge Coding Others

Quiz: LCS-Root Locus

To View Tricks: Login Required

Number of Questions: 17

Question: 1 -

The gain margin for the system with open loop transfer function

G(s)H(s) = 2(1+s)/s2

Options:

  1. ∞

  2. -∞

  3. 0

  4. 1

    5. Answer:

    ∞
    Solution:

    ∠G(s)H(s) = −180° + tan−1ω

Question: 2 -

The feedback control system in the figure is stable.

 

Options:

  1. for all K ≥ 0

  2. only is K ≥ 0

  3. onlyif 0 ≤ K <1

  4. only if 0 ≤ K ≤1

    5. Answer:

    onlyif 0 ≤ K <1
    Solution:

    TF= G1G2/1+H1G1G2

    then use Routh's Array.

Question: 3 -

The characteristic polynomial of a system is

q(s) = 2s5+s4+4s3+2s2+2s+1

The system is

Options:

  1. stable

  2. oscillatory

  3. marginally stable

  4. unstable

    5. Answer:

    unstable
    Solution not available.

Question: 4 -

The system shown in the figure remains stable when

Options:

  1. −1< K <1

  2. 1< K < 3

  3. K < −3

  4. K < −1

    5. Answer:

    K < −3
    Solution:

    Y(s)/R(s) = (K/s)/{1-(3/s+k/s)} = K/s-(3+K)

     

Question: 5 -

The phase margin of a system wit the open-loop transfer function

G(s)H(s) = (1-s)/(1+s)(2+s)

Options:

  1. 0°

  2. ∞

  3. 63.4°

  4. 90°

    5. Answer:

    ∞
    Solution:

    |G(s).H(s)|= 1