Chemical Engineering - Process Control and Instrumentation

41. 

Temperature of molten pig iron (1450°C) and molten slag (1500°C) flowing out of a blast furnace is measured by a/an

A. chromel-alumel thermocouple
B. optical pyrometer
C. radiation pyrometer
D. either (b) or (c)

Answer: Option D

Explanation:

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42. 

For two non-interacting first order systems connected in series, the overall transfer function is the __________ of the individual transfer functions.

A. product
B. ratio
C. sum
D. difference

Answer: Option A

Explanation:

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43. 

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.

A. 250
B. 350
C. 550
D. 700

Answer: Option C

Explanation:

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44. 

Mercury thermometer is commonly used for low temperature measruement. The freezing point and boiling point of mercury are respectively __________ °C.

A. - 39 and 350
B. - 51 and 439
C. - 79 and 395
D. - 10 and 425

Answer: Option A

Explanation:

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45. 

Which of the following thermocouples has the least temperature measurement range?

A. Copper-constantan
B. Chromel-alumel
C. Platinum-platinum/rhodium
D. Iron-constantan

Answer: Option A

Explanation:

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