Consider a cubic body 20 cm × 20 cm × 20 cm at 750 K suspended in air. Assuming that the body closely approximates a black body, determine (a) the ratio of the which the cube emits radiation energy, in W, and b) the spectral emission power of body black at a wavelength of 4 mm. As =? Eb =? Ebλ =?

Consider a cubic body 20 cm × 20 cm × 20 cm at 750 K suspended in air. Assuming that the body closely approximates a black body, determine (a) the ratio of the which the cube emits radiation energy, in W, and b) the spectral emission power of body black at a wavelength of 4 mm. As =? Eb =? Ebλ =?

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.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.24P: Two large parallel plates with surface conditions approximating those of a blackbody are maintained...

See similar textbooks

Similar questions

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.
1.28 The sun has a radius of and approximates a blackbody with a surface temperature of about 5800 K. Calculate the total rate of radiation from the sun and the emitted radiation flux per square meter of surface area.
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.
Determine the total average hemispherical emissivity and the emissive power of a surface that has a spectral hemispherical emissivity of 0.8 at wavelengths less than 1.5m, 0.6 at wavelengths from 1.5to2.5m, and 0.4 at wavelengths longer than 2.5m. The surface temperature is 1111 K.
A tungsten filament is heated to 2700 K. At what wavelength is the maximum amount of radiation emitted? What fraction of the total energy is in the visible range (0.4to0.75m)? Assume that the filament radiates as a graybody.
11.41 Determine the steady-state temperatures of two radiation shields placed in the evacuated space between two infinite planes at temperatures of 555 K and 278 K. The emissivity of all surfaces is 0.8.
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 .
The filament of a 75-W light bulb may be considered a blackbody radiating into a black enclosure at 70°C. The filament diameter is 0.10 mm, and the length is 5 cm. Considering only radiation, determine the filament temperature.
Light from an ideal spherical blackbody 15.0 cm in diameteris analyzed by using a diffraction grating that has 3850 lines/cm.When you shine this light through the grating, you observe that thepeak-intensity wavelength forms a first-order bright fringe at +-14.4from the central bright fringe. (a) What is the temperature of the blackbody?(b) How long will it take this sphere to radiate 12.0 MJ of energyat constant temperature?