11. A constant volume gas thermometer employing _________ is used to measure sub-zero (i.e., <0°C) temperature.
Correct answer: (A)
Helium
12. A control system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at the crossover frequency. This is _________ criterion.
Correct answer: (A)
Bode stability
13. A first order system with a time constant of 1 min is subjected to frequency response analysis. At an input frequency of 1 radian/min, the phase shift is
Correct answer: (D)
-45°
14. 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
Correct answer: (C)
1/√2
15. A magnetic flowmeter is
Correct answer: (D)
All (A), (B) and (C)
16. A manometer measures the _________ pressure.
Correct answer: (C)
Gauge
17. A mercury barometer measures the _________ pressure.
Correct answer: (A)
Atmospheric
18. A mercury thermometer cannot be used to measure the temperature below the freezing point of mercury, which is _________ °C.
Correct answer: (A)
-38.9
19. A negative gain margin expressed in decibels means a/an _________ system.
Correct answer: (B)
Unstable
20. A non-linear chemical system is exemplified by a/an
Correct answer: (C)
Non-isothermal CSTR