Consider two rectangular surfaces perpendicular to each other with a common edge which is 1.6 mlong. The horizontal surface is 0.8 m wide and the vertical surface is 1.2 m high. The horizontal surface has anemissivity of 0.75 and is maintained at 400 K. The vertical surface is black and is maintained at 550 K. The backsides of the surfaces are insulated. The surrounding surfaces are at 290 K, and can be considered to have anemissivity of 0.85. Determine the net rate of radiation heat transfers between the two surfaces, and betweenthe horizontal surface and the surroundings.A. 2245 W, 725 WT2 = 275 KE2 = 1T; = 300 KEz = 1%3DB. 1245 W, 725 WC. 1245 W, 825 WD. 2245 W, 825 WDTj = 425 KEj = 1-)

1. Steady operating conditions exist 2. The surfaces are opaque, diffuse, and gray 3. Convection…

Answered: emissivity of 0.85. Determine the net…

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

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Consider a surface at a uniform temperature of 800 K. Determine the maximum ratioof thermal radiation that can be emitted by this surface, in W / m2
2_5190874259647370... A cylindrical shape is with diameter of 1.2m and length of 1.2m. The top surface has an emissivity of 0.7 and temperature 500 K. The bottom surface has an emissivity of o.5 and temperature 650 K. The side surface has an emissivity of 0.4. Determine the shape factors for all surfaces. E 0.0 L=650 K II >
A 2-m-internal-diameter double-walled spherical tank is used to store iced water at 0°C. Each wall is 0.5 cm thick, and the 1.5-cm-thick air space between the two walls of the tank is evacuated in order to minimize heat transfer. The surfaces surrounding the evacuated space are polished so that each surface has an emissivity of 0.15. The temperature of the outer wall of the tank is measured to be 20°C. Assuming the inner wall of the steel tank to be at 0°C, determine (a) the rate of heat transfer to the iced water in the tank and (b) the amount of ice at 0°C that melts during a 24-h period.
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A particular furnace is shaped like a section of a cone. The top surface of the furnace is uniformly heated by a resistance heater. During operation, the top surface is measured to be 800 K and the power supplied to the resistance heater is 1750 W/m². The sidewall of the furnace is perfectly insulated with & = 0.2. If the emissivity of the top and bottom surfaces are ε = 0.5 and ε = 0.7, respectively, determine the temperatures of the sidewall and the bottom surface of the furnace. A₁ A2 A3 →→D₂ = 20 mm D₁ = 40 mm L = 50 mm
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emissivity of 0.85. Determine the net rate of radiation heat transfers between the two surfaces, and between the horizontal surface and the surroundings.