Q. Two radiating surface A 1 = 6 m² and A 2 = 4 m² have shape factor F 12 = 0.1. Then the shape factor F 21 will be

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Q. What is the value of shape factor for two infinite parallel surfaces separated by a distance x?

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Q. What is the shape factor of a sphere of diameter d inside a cubical box of length l = d?

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Q. What is the shape factor of hemispherical surface closed by a plane surface of diameter d?

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Q. Establish a relation for shape factor for a conical cavity with respect to itself of depth h and diameter d. The cavity is closed on its outer surface with a flat plate

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Q. What is the shape factor for a hemispherical bowl with respect to itself of diameter d? The cavity is closed on its outer surface with a flat plate

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Q. Consider a system of concentric spheres of radius r 1 and r 2 (r 2 is greater than r 1). If r 1 = 5 cm, determine the radius r 2 if it is desired to have the value of shape factor F 21 equal to 0.6

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Q. In the given diagram let r be the length of the line of propagation between the radiating and the incident surfaces. What is the value of solid angle W?

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Q. Consider two surfaces, one absolutely black and the other non-black. These surfaces are arranged parallel to each other and so close that the radiation of one falls totally on the other. Choose the correct option

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Q. The solid angle is defined by a region by the rays of a sphere, and is measured as

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Q. The plane angle is defined by a region by the rays of a circle, and is measured as

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Q. When the incident surface is a sphere, the projection of surface normal to the line of propagation is the silhouette disk of the sphere which is a circle of the diameter of

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Q. If I n denotes the normal intensity and I α represents the intensity at angle α, then

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Q. The intensity of normal radiation In is how much times the emissive power?

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Q. A small surface emits diffusively, and measurements indicate that the total intensity associated with emission in the normal direction I n = 6500 W/square m sr. The emitted radiation is intercepted by three surfaces. Mark calculations for intensity associated with emission

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Q. Consider a deep-space probe constructed as 1 m diameter polished aluminum sphere. Estimate the equilibrium temperature that the probe reaches if the solar energy received is 300 W/m². For solar radiation, absorptivity of aluminum is 0.3 and the average emissivity appropriate for aluminum at low temperature is 0.04

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Q. The total emissive power of the emitter with area d A and temperature T is given by

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Q. A black body of 0.2 m² area has an effective temperature of 800 K. Calculate the intensity of normal radiations

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Q. The energy radiated out decreases with increases in α and becomes zero at an angle of

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Q. Find the shape factor F 12 for the arrangement shown in the figure. The areas A 1 and A 2 are perpendicular but do not share the common edge

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