Heat and Mass Transfer
Depending on the radiating properties, body will be transparent when(Where a = absorptivity, p = reflectivity, x = transmissivity)

P = 0, x = 0 and a = 1
X = 0, a + p = 1
P = 0, x= 1, and a = 0
P=1, x = 0, and a = 0

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Heat and Mass Transfer
According to Prevost theory of heat exchange

All bodies above absolute zero emit radiation
Heat transfer by radiation requires no medium
It is impossible to transfer heat from low temperature source to t high temperature source
Heat transfer in most of the cases takes place by combination of conduction, convection and radiation

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