Test: Emissivity


10 Questions MCQ Test Mass Transfer | Test: Emissivity


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This mock test of Test: Emissivity for Chemical Engineering helps you for every Chemical Engineering entrance exam. This contains 10 Multiple Choice Questions for Chemical Engineering Test: Emissivity (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Emissivity quiz give you a good mix of easy questions and tough questions. Chemical Engineering students definitely take this Test: Emissivity exercise for a better result in the exam. You can find other Test: Emissivity extra questions, long questions & short questions for Chemical Engineering on EduRev as well by searching above.
QUESTION: 1

 What is the value of emissivity for polished aluminum?

Solution:

Explanation: The emissivity of the surface of a material is its effectiveness in emitting energy as thermal radiation.

QUESTION: 2

Which one is having highest emissivity?

Solution:

Explanation: Emissivity of tarnished copper is 0.75 while that of polished aluminum, aluminum foil and polished copper are 0.03, 0.05 and 0.03 respectively.

QUESTION: 3

 What is the value of emissivity for polished copper?

Solution:

Explanation: This is the total hemispherical emissivity from the surfaces. It describes thermal radiation emitted near specific wavelength and at specific angles to surface.

QUESTION: 4

What is the value of emissivity for tarnished copper?

Solution:

Explanation: This is optically thick material. The absorptivity at the wavelengths doesn’t depend on the thickness of the material.

QUESTION: 5

Which one is having lowest emissivity?

Solution:

Explanation: Emissivity of polished stainless steel is 0.60 while that of white marble, snow and asphalt are 0.95, 0.97 and 0.90 respectively.

QUESTION: 6

 What is the value of emissivity for dull stainless steel?

Solution:

Explanation: It is transparent with low emissivity coatings. It emits less thermal radiation than ordinary window.

QUESTION: 7

 What is the value of emissivity for white marble?

Solution:

Explanation: It is based on evacuated glass tube collectors. Sunlight is absorbed by a selective surface.

QUESTION: 8

Which one is having highest emissivity?

Solution:

Explanation: Emissivity of black paint is 0.97 while that of red brick, concrete and dull stainless steel are 0.93, 0.88 and 0.21 respectively.

QUESTION: 9

What is the value of emissivity for asphalt?

Solution:

Explanation: It is an ordinary black surface that absorbs sunlight efficiently but emit thermal radiation copiously.

QUESTION: 10

Which one is having lowest emissivity?

Solution:

Explanation: Emissivity of polished stainless steel is 0.60 while that of snow, white marble and concrete are 0.97, 0.95 and 0.88 respectively.

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