Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
8th Edition
ISBN: 9781305387102
Author: Kreith, Frank; Manglik, Raj M.
Publisher: Cengage Learning
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Textbook Question
Chapter 11, Problem 11.2P
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
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Chapter 11 Solutions
Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)
Ch. 11 - A tungsten filament is heated to 2700 K. At what...Ch. 11 - Determine the total average hemispherical...Ch. 11 - Prob. 11.4PCh. 11 - Prob. 11.9PCh. 11 -
11.31 A large slab of steel 0.1 m thick contains...Ch. 11 - Prob. 11.32PCh. 11 - 11.41 Determine the steady-state temperatures of...Ch. 11 - Three thin sheets of polished aluminum are placed...Ch. 11 - 11.68 Two infinitely large, black, plane surfaces...
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- Calculate the radiation in watts per square centimeter from a block of copper at 200°C and at 1000°C. The oxidized copper surface radiates at 0.60 the rate of a black body.arrow_forwardA thin tungsten filament with a length of 1.47 m radiates 60.2 W of power in the form of electromagnetic waves. A perfectly absorbing surface, in the form of a hollow cylinder with a radius of 5.09 cm and a length of 1.47, is placed concentrically with the filament. Calculate the radiation pressure acting on the cylinder. (Assume that the radiation is emitted in the radial direction, and neglect end effects.)arrow_forwardThe reflectivity of aluminum coated with lead sulfate is 0.35 for radiation at wavelengths less than 3 mm and 0.95 for radiation greater than 3 mm. Determine the average reflectivity of this surface for solar radiation (T < 5800 K) and radiation coming from surfaces at room temperature (T < 300 K). Also, determine the emissivity and absorptivity of this surface at both temperatures. Do you think this material is suitable for use in solar collectors?arrow_forward
- A small 100 cd spring is located in the center of a spherical mirror with a diameter of 10 cm and a focal length of 50 cm. Assuming that the total reflectance is about 80%, obtain the average brightness of the parallel beam reflected from the mirror.arrow_forwardThe tungsten filament of an incandescent light bulb has a temperature of approximately 3000 K. The emissivity of tungsten is approximately 1/3, and you may assume that it is independent of wavelength. To increase the efficiency of an incandescent bulb, would you want to raise or lower the temperature? (Some incandescent bulbs do attain slightly higher efficiency by using a different temperature.)arrow_forwardList this type of electromagnetic radiation in order of (i) increasing wavelength and (ii) increasing energy per photon: Infrared radiationarrow_forward
- List this type of electromagnetic radiation in order of (i) increasing frequency and (ii) decreasing energy per photon: Gamma raysarrow_forward3. 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?arrow_forwardA 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:arrow_forward
- 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.arrow_forwardLight 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 +-14.4 from 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?arrow_forward
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