Q. A gray body (E = 0.8) emits the same amount of heat as a black body at 1075 K. Find out the required temperature of the gray body

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Q. The heat energy absorbed by a known area in a fixed time is determined with the help of an instrument called

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Q. The value of solar constant varies between

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Q. The total amount of heat energy received by the sphere of radius r is

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Q. Amount of heat energy radiated by unit surface of the sun in the same time workout as
Take, R = mean distance of earth from the sun and r = radius of sun

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Q. Temperature of sun can be workout from

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Q. The temperature of the photosphere, referred to as the effective temperature of the sun, is usually taken as

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Q. The approximate distribution of the flow of sun’s energy to the earth’s surface is

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Q. The solar radiation that is felt at the earth’s surface includes

(i) Direct radiation that has passed through the atmosphere

(ii) Diffuse radiation from the sky

(iii) Absorbed radiation from the water

Identify the correct statement

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Q. When the sun lies at a mean distance from the earth, the heat flux from the sun to the outer edge of the atmosphere has been found to be

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Q. Which one is having highest value of solar absorptivity?

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Q. What is the value of solar absorptivity for aluminum foil?

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Q. What is the value of solar absorptivity for polished copper?

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Q. Which one is having lowest value of solar absorptivity?

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Q. What is the value of solar absorptivity for polished stainless steel?

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Q. What is the value of solar absorptivity for white marble?

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Q. What is the value of solar absorptivity for asphalt?

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Q. What is the value of solar absorptivity for snow?

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Q. Engineering problems of practical interest are involved with heat exchange between two or more surfaces, and this exchange is strongly dependent upon

(i) Radiative properties

(ii) Temperature levels

(iii) Surface geometrics

Identify the correct statements

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Q. The fraction of the radiative energy that is diffused from one surface element and strikes the other surface directly with no intervening reflections is called

(i) Radiation shape factor

(ii) Geometrical factor

(iii) Configuration factor

Choose the correct answer

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