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

View solution

Q. Temperature of sun can be workout from

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

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

View solution

Q. The interchange factor is also known as

View solution

Q. For the same type of shapes, the value of radiation shape factor will be higher when

View solution

Q. A thin shield of emissivity E3 on both sides is placed between two infinite parallel plates of emissivities E1 and E2 and temperatures T1 and T2. If E1 = E2 = E3, then the fraction radiant energy transfer without shield takes the value

View solution

Q. The grey body shape factor for radiant heat exchange between a small body (emissivity = 0.4) in a large enclosure (emissivity = 0.5) is

View solution