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ECE :: Automatic Control Systems

  1. Assertion (A): If the Laplace transform is , the Laplaces transform of impulse response is given by

    Reason (R): The Laplace transform for an impulse function is 1.

  2. 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

  3. The polar plot of is the negative imaginary axis.

  4. A.
    True
    B.
    False

  5. In the given figure, P = Pm sin ωt. Then X(s) =


  6. The number of branches of root locus plot is equal to

  7. 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

  8. The action of bellows is similar to that of

  9. A.
    mass
    B.
    viscous friction
    C.
    spring
    D.
    none of the above

  10. The given figure shows three Nyquist plots of G(s) H(s) = e-sT/[s(s + 1)] for different values of T. The curves 1, 2, 3 can be

  11. A.
    for T = 0, 0.5 and 1 respectively
    B.
    for T = 1, 0.5 and 0 respectively
    C.
    for T = 0.5, 1 and 0 respectively
    D.
    for T = 0, 1 and 0.5 respectively

  12. Consider the following statements:
    The gain margin and phase margin of an unstable system may respectively be

    1. positive, positive
    2. positive, negative
    3. negative, positive
    4. negative, negative
    Of these statements

  13. A.
    1, 4 are correct
    B.
    1 and 2 correct
    C.
    1, 2, 3 are correct
    D.
    2, 3, 4 are correct

  14. A first order element yields almost exact duplication only for constant or slowly varying phenomenon.

  15. A.
    True
    B.
    False

  16. For a stable system

  17. A.
    both phase and gain margin are negative
    B.
    both phase and gain margin are positive
    C.
    phase margin is positive but gain margin is negative
    D.
    gain margin is positive but phase margin is negative

  18. If the angle of departure of root locus at s = - 1 + j is

  19. A.
    zero
    B.
    90°
    C.
    -90°
    D.
    -180°