ASAP please (a)Two surfaces, A and B has a temperature of 4500 K and different spectralemissivity as shown in Figure 3.1. By assuming Stefan Boltzmann constant is5.67 x 10* W/m²-K', determine:i.the average emissivity for each surface,emissive power for each surface,iii.wavelength of surface A at which spectral emissive power will be amaximum, andiv.which surface is more suitable as a solar absorber? Justify your answer.0.70.60.20.20.10.1A. umA. um(a)(b)Figure 3.1 Variation of spectral; (a) Surface A, (b) Surface B

Given: The temperature, T = 4500 K The Stefan Stefan Boltzmann’s constant, σ = 5.67x10^-8 W/m^2.K

(a) Two surfaces, A and B has a temperature of 4500 K and different spectral emissivity as shown in Figure 3.1. By assuming Stefan Boltzmann constant is 5.67 x 10* W/m-K', determine: i. the average emissivity for each surface, ii. emissive power for each surface, wavelength of surface A at which spectral emissive power will be a maximum, and

(a) Two surfaces, A and B has a temperature of 4500 K and different spectral emissivity as shown in Figure 3.1. By assuming Stefan Boltzmann constant is 5.67 x 10* W/m-K', determine: i. the average emissivity for each surface, ii. emissive power for each surface, wavelength of surface A at which spectral emissive power will be a maximum, and

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter11: Heat Transfer By Radiation

Section: Chapter Questions

Problem 11.3P: Determine the total average hemispherical emissivity and the emissive power of a surface that has a...

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11.31 A large slab of steel 0.1 m thick contains a 0.1 -m-di- ameter circular hole whose axis is normal to the surface. Considering the sides of the hole to be black, specify the rate of radiative heat loss from the hole. The plate is at 811 K, and the surroundings are at 300 K.
11.68 Two infinitely large, black, plane surfaces are 0.3 m apart, and the space between them is filled by an isothermal gas mixture at 811 K and atmospheric pressure. The gas mixture consists of by volume. If one of the surfaces is maintained at 278 K and the other at 1390 K, calculate (a) the effective emissivity of the gas at its temperature, (b) the effective absorptivity of the gas to radiation from the 1390 K surface, (c) the effective absorptivity of the gas to radiation from the 278 K surface, and (d) the net rate of heat transfer to the gas per square meter of surface area.
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1.26 Repeat Problem 1.25 but assume that the surface of the storage vessel has an absorbance (equal to the emittance) of 0.1. Then determine the rate of evaporation of the liquid oxygen in kilograms per second and pounds per hour, assuming that convection can be neglected. The heat of vaporization of oxygen at –183°C is .
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