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?

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?

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...

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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.
Two large parallel plates with surface conditions approximating those of a blackbody are maintained at 816C and 260C, respectively. Determine the rate of heat transfer by radiation between the plates in W/m2 and the radiative heat transfer coefficient in W/m2K.
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.
Two parallel gray planes that are very large have emissivities of ε1 = 0.8 and ε2 = 0.7; surface 1 is at 1100°F (866.5 K) and surface 2 is at 600°F (588.8 K). Use SI units for the following: (a) What is the net radiation from 1 to 2? (b) If the surfaces are both black, what is the net radiation?
Find the emissive power of a black body with surface temperature of 1000 K and wavelengthof (1) μm. uses charts/table also if needed
A 0.6m diameter sphere is suspended in an enclosure. The ball is kept at aconstant 200oC, while the enclosure is kept at 25oC. a) If the enclosure is opaque, how much radiation is emitted by the ball into the enclosure? b) If the enclosure is not opaque, it does not form a black body. Let’s say the enclosure has a transmissivity of 0.6 and a reflectivity of 0.2. How much thermal radiation is absorbed by the enclosure?
3. Two parallel plates with a diameter of 60 cm, separated at a distance of 15 cm. The temperature on the top surface is 4 oC and the temperature on the bottom surface is 300 K. If all the surfaces are black, what is the rate of heat transfer?
A typical car's exterior consists of a thin layer of silica (SiO2) over an opaque painted metal panel. Silica is transparent in the visible wavelengths but offers high reflectance in the near- to mid- infrared wavelengths. The plot on the next page depicts the diffuse spectral reflectivity (pa) of the car's surface: Spectral reflectivity, P₂ 0.8 0.6 0.4 ལ 0.2 0 0.1 1 1 10 Wavelength, λ(μm) 100 If the car's exterior temperature is T₁ = 77°C, determine both the total absorptivity (a) and the total emissivity (a) of the silica-covered panel. Assume that the Sun's temperature is Tsun = 5800 K.
Two concentric spheres of diameter D = 0.8 m and D2 = 1.2 m are separated by an air space and have surface temperatures of T = 400 K and T2 = 300 K. (a) If the surfaces are black, what is the net rate of radiation exchange between the spheres, in W? 912 = (b) What is the net rate of radiation exchange between the surfaces if they are diffuse and gray with e = 0.5 and e2 = 0.05, in W? 912 = W (c) What is the net rate of radiation exchange if D2 is increased to 20 m, with ɛz = 0.05, ɛ1 = 0.5, and D = 0.8 m, in W? 912 = w (d) What is the net rate of radiation exchange if the larger sphere behaves as a black body (82 = 1.0) and with & = 0.5, D2 = 20 m, and D = 0.8 m, in W? 912 = W
A half cylindrical shell with a radius of 75 cm is held at 200°C and has an emissivity of 0.4. A long 200°C R= 75 cm cylinder has a diameter of 30 cm and is placed 20°C E= 0.4 D= 30 cm concentrically with the shell. The cylinder is radiatively black. At the instant the cylinder is 20°C, how much heat is exchanged from the shell to the cylinder, per meter length into the page, i.e., Qshell-eylinder/L.
A light of a given wavelength is shining through a double slit plate with slits of width a and slit separation d which produces a diffraction pattern on a screen some distance away. If the intensity pattern for the double slit diffraction aspect of this setup is: And the intensity pattern for the single slit diffraction aspect of this setup is: Which of the following intensity plots best represents what you would see on the screen: