Q. Assertion (A): An on off controller gives rise to oscillation of the output between two limits.

Reason (R): Location of a pair of poles on jω axis gives rise to self sustained oscillations in the output.

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Q. Consider the following statements about transport-lag

1. It is of non-minimum phase behaviour
2. It normally exists in thermal, hydraulic and pneumatic systems
3. It has an excessive phase lag with no attenuation at high frequency

Which of the above statements are correct?

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Q. Consider the following statements:

1. If any root of characteristic equation has a positive real part the impulse response is unbounded and system is unstable.
2. If all the roots of a characteristic equation have negative real parts, the impulse response decays to zero.
3. If one or more non-repeated roots of characteristic equation are on jω axis impulse response is bounded but the system is unstable.

Which of the above equations are correct?

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Q. In root locus analysis the breakaway and break in points

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Q. Gain margin and phase margin can be determined from Bode plots as well as Nyquist plot.

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Q. For the factor (1 + 0.5 jω) the corner frequency is

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Q. For any transfer function, the constant phase angle loci are

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Q. For an m x n matrix A, the eigen values are the roots of the characteristic equation

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Q. In force current analogy, displacement x is analogous to

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Q. Consider the following statements about variable reluctance stepper motor used in control system

1. The static torque acting on rotor is a function of angular misalignment between stator and rotor teeth
2. There are two positions of zero torque i.e, . Q = 0 and 180°/T where T is the number of rotor teeth
3. Both zero torque positions are stable
4. When stator is excited, rotor is pulled into minimum reluctance position

Of these statements, the correct ones are

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Q. In a two phase servomotor the two stator windings have a phase difference of

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Q. For a stable system having two or more gain crossover frequencies the phase margin is measured at the highest crossover frequency.

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Q. In a two phasor servomotor, the direction of rotation of the rotating field depends on

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Q. Assertion (A): Points in the s plane at which function G(s) is not analytic are called singular, points.

Reason (R): Singular points at which the function G(s) or its derivative approach infinity are called poles.

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Q. If damping ratio is 0.5, the lines joining complex poles with origin are inclined to negative real axis at

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Q. At corner frequency the phase angle of factor 1/(1 + jωT) is - 45°

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Q. The permanent magnet field system of brushless dc servo- motor is generally on

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Q. Assertion (A): The phase angle plot in Bode diagram is not affected by change in system gain.

Reason (R): The variation in gain has no effect on phase margin of the system.

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Q. The phase difference (jω - p1) means

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Q. If poles lie in first quadrant, damping ratio is

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