Two long parallel surfaces each of emissivity 0.7 are maintained at di – McqOptions

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1.	Two long parallel surfaces each of emissivity 0.7 are maintained at different temperatures and accordingly have radiation heat exchange between them. It is desired to reduce 75% of the radiant heat transfer by inserting thin parallel shields of emissivity 1 on both sides. The number of shields should be
A.	one
B.	two
C.	three
D.	four
Answer» D. four

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