Q. For a grey surface

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Q. Which quantity can be neglected for gases?

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Q. Absorptivity of a body is equal to its emissivity

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Q. Electromagnetic waves strikes a hot body maintained at 900 degree Celsius which has a reflectivity of 0.66 and a transmissivity of 0.022. Let the absorbed flux be 60 W/m². Determine the rate of incident flux

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Q. Radiation heat transfer is characterized by

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Q. Which is true regarding radiation?

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Q. Radiation exchange occurs in

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Q. Energy released by a radiating surface is not continuous but is in the form of successive and separate packets of energy called

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Q. The electromagnetic waves are emitted as a result of

(i) Vibrational movement
(ii) Rotational movement
(iii)Atomic or sub-atomic particles comprising the matter

Identify the correct statement

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Q. Thermal radiations occur in the portion of electromagnetic spectrum between the wavelengths

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Q. A perfectly black body

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Q. What is the wavelength band for cosmic rays?

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Q. For a prescribed wavelength a black body radiates how much energy at the temperature of body?

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Q. “Radiation emitted by a black surface is a function of wavelength and temperature but is independent of direction”. Choose the correct answer

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Q. The distribution of radiant energy is non uniform with respect to

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Q. “Spatial distribution is also known as directional distribution”. Choose the correct option

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Q. Thermal radiation strikes a surface which has a reflectivity of 0.55 and transmissivity of 0.032. A quantity known as flux is found out to be 95 W/m². Determine the rate of incident flux.

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Q. What is the wavelength for visible light?

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Q. 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 absorption

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Q. 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/m² K, workout the reflectivity of the plate

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