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.Management Sciences
Category: Process Control and Instrumentation
The temperature of tempering oil baths maintained at 400°C during heat treatment of steel is measured by a/an _____________ thermocouple?
A. Chromel-alumel
B. Iron-constantan
C. Platinum-platinum/rhodium
D. None of these
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
Pick out the most suitable instrument for measuring temperature in the range of-40 to 425°C ?
A. Mercury thermometer
B. Bimetallic thermometer
C. Radiation pyrometer
D. None of these
Temperature of _____________ cannot be measured by an optical or radiation pyrometer?
A. Hot blast (air) from stoves
B. Molten slag flowing out of blast furnace
C. Combustion space in boilers
D. Rotary limestone calcination kiln
Instrumentation in a plant offers the advantage of_______________?
A. Greater safety of operation
B. Better quality of product
C. Greater operation economy
D. All A., B. and C.
Working principle of mercury in glass thermometer is based on the ______________ of mercury with increase in temperature?
A. Increase of pressure
B. Increase of thermal conductivity
C. Volumetric expansion
D. Differential linear expansion
Cascade control means _______________?
A. Feed forward control
B. More than one feed-back loop
C. On-off control
D. One feed-back loop
Minute depression of freezing point of a liquid solvent on addition of a solid solute can be best measured by a________________?
A. Beckman thermometer
B. Dilatometer
C. Mercury thermometer
D. Bimetallic thermometer
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
Continuous measurement of moisture content of paper in paper industry is done by measuring the_________________?
A. Thermal conductivity through the paper
B. Electrical resistance through the paper
C. Magnetic susceptibility
D. None of these
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