The emissivity of a tungsten filament can be approximated to be 0.5 for radiation at wavelengths less than 1 mm and 0.15 for radiation at greater than 1 mm. Determine the average emissivity of the filament at (a) 2000 K and (b) 3000 K. Also, determine the absorptivity and reflectivity of the filament at both temperatures.

The emissivity of a tungsten filament can be approximated to be 0.5 for radiation at wavelengths less than 1 mm and 0.15 for radiation at greater than 1 mm. Determine the average emissivity of the filament at (a) 2000 K and (b) 3000 K. Also, determine the absorptivity and reflectivity of the filament at both temperatures.

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 11.2P: A tungsten filament is heated to 2700 K. At what wavelength is the maximum amount of radiation...

See similar textbooks

Related questions

Q: Consider a blackbody at 300K with maximum emissive power. Calculate the wavelength (μm) of the…

A: In the graph of emissive power and wavelength of the radiation, it is observed that at a particular…

Q: Calculate the view factor FBA for the following shape. The radii for the hollow circle, circle A…

A: Given :- Circle A radii : Outer Radius (R) = 8 m Inner Radius (r) = 5 m Circle B radius : Radius…

Q: 2. Calculate the view factor FBA for the following shape. The radii for the hollow circle, circle A…

A: Given that, Radius of hollow circle A, rA=8 m, and RA=10 m,Radius of circle B, RB=5 m,Vertical…

Q: Calculate the ratio of the radiant energy emitted from a surface at 37ºC and an adjacent surface of…

A: Given: The surface temperature, T1 = 37 C The adjacent surface temperature, T2 = 35 C

Q: A body at 1100ºc in a black surrounding at 550ºc has emissivity of 0.4 at 1100ºc and emissivity 0.7…

Q: A horizontal opaque flat plate is well insulated on the edges and the lower surface. The top surface…

Q: You are using a heated cylindrical tube blackbody as a chamber for an experiment. The tube is 2m…

Q: the total power emitted by a Black Body at a temperature of 2000 K with wavelength range A= 1.5 um –…

Q: What properties are required to determine the view factors between two surfaces Emissivity of…

A: What properties are required to determine the view factors between two surfaces Emissivity of…

Q: The surface temperature of the sun is about 6000K. Accordingly, which wavelength corresponds to the…

A: Given: The maximum temperature, T = 6000 K

Q: Consider a 20-cm-diameter spherical ball at 800 K suspended in air. Assuming the ball closely…

A: Given data as per question Diameter of sphere = 20 cm Sphere temperature = 800 k wavelength = 3um

Q: Determine the view factors from the base of the pyramid shown in Figure 12-14 to each of its four…

Q: 1.5) Fill in the blanks: A body whose surface properties are independent of wavelength is said to be…

Q: 13–19 Determine the view factors F13 and F3 between the rectangular surfaces shown in Fig. P13–19.

A: It is required to determine view factors F13 and F23 between the rectangular surfaces of the given…

Q: Consider a blackbody at 300K with maximum emissive power. Calculate the wavelength (Im) of the…

Q: the outer surface temperature of the furnace should be kept below 45°C. Based on the above…

Q: Based upon the reradiating properties of absorptivity, reflectivity and transmissivity, how would…

A: For any body absorptivity is defined by factor α, reflectivity is defines by ρ and transmissivity by…

Q: (b) A black body in vacuum emits maximum radiation at wavelength 0.6x10° m. Estimate the : (1)…

A: Ans.4(b) Given Data Wavelength of the black body, 0.6×10-6m

Q: The reflectivity of aluminum coated with lead sulfate is 0.35 for radiation at wavelengths less than…

A: The given value for the surface wavelength less than 3 μm is The given value for the surface…

Q: urfaces A and B are concentric cylindrical tubes with diameters of 275 and 300 mm, respectively.…

Q: 2000 degrees * C The temperature of the filament of an incandescent light bulb is . Assuming the…

A: Heat transfer is the form of energy transfer which transfers from one system to another system by…

Q: The filament of a 75-W light bulb may be considered a blackbody radiating into a black enclosure at…

A: Given Data Energy radiated per second is: q=75 W Length of the filament is: l=5 cm=0.05 m The…

Q: A horizontal plate is experiencing uniform irradiation on the both upper and lower surfaces. The…

A: Given data Temperature of air Ta= 290K Heat transfer coefficient h = 3030 W/m2K Radiosity of the…

Q: Consider a cubic body 20 cm × 20 cm × 20 cm at 750 K suspended in air. Assuming that the body…

Q: 8. A black body has an effective surface temperature of rmine: (a) The total radiation energy (W/m²)…

Q: A 0.6m diameter sphere is suspended in an enclosure. The ball is kept at a constant 200oC, while…

Q: A cylindrical shape is with diameter of 1.2m and length of 1.2m. The top surface has an emissivity…

Q: The peak wavelength of radiation emitted by a black body at a temperature of 1000 K is 1.35 um. If…

Q: A gray body with a constant surface temperature of 7000C and a surface area of 500cm2 radiates in a…

Q: Consider two infinitely long thin concentric tubes of circular cross section as shown in figure. If…

Q: An opaque surface at 1000 K if its spectral emissivity is = 0.4, 0.7, and 0.3 for 0 < < 2 μm, 2μm =…

Q: o surfaces, A and B has a temperature of 4500 K and different spectral ssivity as shown in Figure…

Q: A black body has a temperature of 3000 Kelvin. What is the wavelength of peak radiation emanating…

Q: C, emissivity1 = 0.85 and T2 = 35 deg C, emissivity2 = 0.5, respectively. Assu n are diffuse-gray…

Q: A furnace that has a 40-cm * 40-cm glass window can be considered to be a blackbody at 1200 K. If…

A: Given data Area of the glass window = Temperature of the furnace = 1200 K Transmissivity

Q: For a surface, how is irradiation defined? For diffusely incident radiation, how is irradiation on a…

Q: The temperature of the filament of an incandescent lightbulb is 3200 K. Treating the filament as a…

A: Radiation fraction is calculated for visible range 0.4 to 0.76 micrometer. Given: visible range =…

Q: Define the absorption of radiation incident on an opaque surface of absorptivity α.

A: Define the absorption of radiation incident in an opaque surface of absorptivity α

Question

The emissivity of a tungsten filament can be approximated
to be 0.5 for radiation at wavelengths less than 1 mm and
0.15 for radiation at greater than 1 mm. Determine the average
emissivity of the filament at (a) 2000 K and (b) 3000 K.
Also, determine the absorptivity and reflectivity of the filament
at both temperatures.

Expert Solution

This question has been solved!

Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.

This is a popular solution!

SEE SOLUTION Check out a sample Q&A here

Step 1

Step 2

Step 3

Step 4

Step 5

Trending now

This is a popular solution!

Step by step

Solved in 5 steps with 8 images

SEE SOLUTION Check out a sample Q&A here

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.

Similar questions

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.
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.
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.
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.
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 .
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.
Determine the rate of radiant heat emission in watts per square meter from a blackbody at (a) 15C, (b) 600C, and (c) 5700C.