When the damping co-efficient (ξ) is unity, the system is __________________?

Related Mcqs:

1. The second order system with the transfer function 4/(s2 + 2s + 4) has a damping ratio of ___________________?

   A. 2.0
   B. 0.5
   C. 1.0
   D. 4.0

2. Working principle of bimetallic thermometers is difference in linear co-efficient of thermal expansion of two strips of different metals welded together. Which of the following has the maximum thermal co-efficient of linear expansion ?

   A. Nickel
   B. Brass
   C. Chromel
   D. Invar

3. A first order system with unity gain and time constant η is subjected to a sinusoidal input of frequency w = 1/η. The amplitude ratio for this system is______________?

   A. 1
   B. 0.5
   C. 1/√2
   D. 0.25

4. According to Bode stability criterion, a system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at frequency for which phase lag is_________________?

   A. 0°
   B. 45°
   C. 90°
   D. 180°

5. “A control system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at the crossover frequency.” This is _______________ criterion?

   A. Bode stability
   B. Nyquist
   C. Routh stability
   D. None of these

6. The time constant of a unity gain, first order plus time delay process is 5 min. If the phase lag at a frequency of 0.2 rad/min is 60°, then the dead time (in minutes) is________________?

   A. 5π/12
   B. π/6
   C. π/12
   D. π/3

7. Thermistor, which has high temperature co-efficient of resistivity, is used as the sensing element in resistance thermometer. It is a/an ?

   A. Insulator
   B. Conductor
   C. Solid semi-conductor
   D. Liquid semi-conductor

8. Thermistors which have a very high temperature co-efficient of resistivity belong to the class of solid called________________?

   A. Dielectrics
   B. Insulators
   C. Semi conductors
   D. Conductors

9. Time constant is the __________________?

   A. Time taken by the controlled variable to reach 63.2% of its full change
   B. Same as transportation lag
   C. Same as dead time
   D. Time required by the measured variable to reach 63.2% of its ultimate change

10. Smoke density of the flue gas going out of the chimney is measured by a __________________?

    A. Polarograph
    B. Thermal conductivity meter
    C. Photo electric cell
    D. Chromatograph