Of the radiant energy 350W/m2 incident upon a surface 250W/m2 is absorbed, 60W/m2 is reflected and the remainder is transmitted through the surface. Workout the value for reflectivity for the surface material
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A thin metal plate of 4 cm diameter is suspended in atmospheric air whose temperature is 290 K. This plate attains a temperature of 295 K when one of its face receives radiant energy from a heat source at the rate of 2 W. If heat transfer coefficient on both surfaces of the plate is stated to be 87.5 W/m 2 K, workout the energy lost by reflection
The value of reflectivity depends upon
(i) Body temperature
(ii) Wavelength of reflected radiation
(iii) Nature of surface of body
Identify the correct statement
When a surface absorbs a certain fixed percentage of striking radiation the surface is called
Radiant energy with an intensity of 800 W/m2 strikes a flat plate normally. The absorptivity is thrice the reflectivity and twice the transmissivity. Determine the rate of reflection
The total radiant energy A impinging upon a body would be partially or totally absorbed, reflected from its surface or transmitted through it. Identify the correct statement