Ordinary mercury in glass thermometer is used for measuring temperature upto 120°C. However, for measuring higher temperature upto __________ °C, thermometer is made by filling nitrogen under pressure above the mercury, which stops the evaporation of mercury and reduces the chance of broken thread of mercury.
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In a feed-back control system G and H denote open loop and close loop transfer functions respectively. The output-input relationship is
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The closed loop pole of a stable second order system could be
A. Both real and positive
B. Complex conjugate with positive real parts
C. Both real and negative
D. One real positive and the other real negative
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When a bare thermocouple is covered by a protective sheath, the response becomes
A. Faster and oscillatory
B. Faster and non-oscillatory
C. Slower and oscillatory
D. Slower and non-oscillatory
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Range of hydrogen gas constant volume themometer is __________ °C.
A. -10 to 20
B. 0 to 100
C. 100 - 500
D. 400 - 1000
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Emf developed by a thermocouple while measuring a temperature of 800°C is about 31 mV. The type of thermocouple used is
A. Chromel-alumel
B. Iron-constantan
C. Platinum-platinum+rhodium
D. None of these
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A photo electric device in which the resistance of the metal is directly proportional to the light striking on it, is known as photo-conductive cell. Photoelectric transducers are used for the measurement of those parameters, which can be used to produce variation in
A. Light intensity
B. Current
C. Flux density
D. Voltage
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Which of the following fluid flow measuring devices can measure the largest flow rate?
A. V-notch
B. Rotameter
C. Orificemeter
D. Weir
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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
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Liquid flow rate in an open channel can not be measured by a/an
A. Orifice meter
B. Cipolletti weir
C. Rectangular weir
D. V-notch
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Which of the following temperature measuring instruments need not touch the object whose temperature is being measured?
A. Radiation/infrared pyrometer
B. Filled system thermometer
C. Mercury in glass thermometer
D. Thermo electric pyrometer
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Emf developed by a thermocouple while measuring a temperature of 400°C is 22 mV. The type of thermocouple used is
A. Chromel-alumel
B. Iron-constantan
C. Platinum-rhodium
D. Platinum-platinum+rhyodium
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Platinum resistance thermometer is the international standard for temperature measurement between
A. Triple point of hydrogen and freezing point of antimony
B. 13.81°K to 903.9°K
C. Both A and B
D. Neither A nor B
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Which of the following thermocouples has the widest temperature measurement range?
A. Iron-constantan
B. Chromel-alumel
C. Copper-constantan
D. Platinum-platinum/rhodium
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Mercury thermometer can be used to measure the temperature upto __________ °C.
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The term analogous to the electrical current in a thermal system is the
A. Temperature difference
B. Heat flow rate
C. Heat content in the system
D. None of these
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What is the normal percentage of rhodium in platinum + rhodium element used in the thermocouple?
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According to Bode stability criterian, a system is unstable, if the open loop frequency response exhibits an amplitude ratio exceeding unity at frequency for which phase lag is
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Accurate temperature measurement performance of a radiation pyrometer can not be affected, if the
A. Enhancement or attentuation of redia-tion occurs in the sighting path
B. Object and surrounding are at almost the same temperature
C. Object has varying emissivity
D. Object is transparent
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Reference points i.e., ice point and steam point in Reaumer temperature scale are respectively
A. - 273° & 80°
B. 0° & 80°
C. 32° & 460°
D. 32° & 80°
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