Elements Of Electromagnetics
7th Edition
ISBN: 9780190698614
Author: Sadiku, Matthew N. O.
Publisher: Oxford University Press
expand_more
expand_more
format_list_bulleted
Related questions
Question
Earth absorbs solar energy and radiates infrared energy. The intensity of the solar radiation incident on earth is J = 1350 Wm-2, also known as the solar constant. Assume earth’s surface (ground) temperature to be uniform at Ts, and that the ground and atmosphere are black (emissivity = 1) for infrared radiation. The radius of the earth is 6.378 x 106 m.
The diagram shows the ground at the surface temperature Ts and the atmosphere, represented as a thin black layer, at temperature Ta . Suppose the atmosphere absorbs 100% of the infrared radiation emitted by the ground. Assume that the ground absorbs 47.5% of the incident solar energy, and that the atmosphere absorbs 17.5% of the incident solar energy (for a total of 65% absorbed by the planet).
Calculate the "steady state” numerical values of the earth’s ground temperature Ts and the atmospheric temperature Ta taking into account the “greenhouse effect” of atmospheric infrared absorption and emission described above.
Transcribed Image Text:atmosphere.
ground
Ta (black)
T₂
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
Trending nowThis is a popular solution!
Step by stepSolved in 3 steps with 2 images
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
- Determine the net heat transfer by radiation between two gray surfaces, A (εA= 0.90) andB (εB= 0.25) at temperatures 500°C and 200°C, respectively if a. surfaces are infinite parallel planes b. surface A is a spherical shell 3 m in diameter and surface B is a similar shell concentric with A and 0.3 m in diameter c. surfaces A and B concentric cylindrical tubes with diameters of 300 mm and 275 mm, respectively d. both surfaces are squares 2 m × 2arrow_forwardQuestion #9 A circular ceramic plate that can be modelled as a blackbody is being heated by an electrical heater. The plate is 30cm in diameter and is situated in a surrounding ambient temperature of 15°C where the natural convection heat transfer coefficient is 12W/m² K. The efficiency of the electrical heater to transfer heat to the plate is 80%, the electric power is required such that the heater needs to keep the surface temperature of the plate at 200°C. Ambient 15°C Tsurr = 15°C h = 12 W/m².K Ceramic plate -T₂ = 200°C Welec (A) Determine the heat emitted from the plate, as a blackbody. (B) Determine the radiation incident on the plate from the surroundings. (C) Determine the heat transfer from the plate to the surroundings. (D) Determine the required electric power.arrow_forwardI need the answer quicklyarrow_forward
- The sonic screwdriver that Dr Who is wielding detects a radiation source that is indicated to be at a 35° angle from the surface normal and 4m from where she is standing. The aperture on the sonic screwdriver has an area of 5.00*10-4 m2 and the source has an area of 0.1 m² with a temperature of 60OK and an emissivity of 0.6. Given a surface irradiation of 8000 W/m2, what is the rate at which the sonic screwdriver intercepts the radiation from the surface? n Ad G r A,arrow_forward1. This problem concerns the difficulty of directly detecting Earth-like planets.The Bond albedo for the Earth is 0.29. Calculate the fraction of the total emitted light fromthe Sun that is reflected by the Earth.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
- Two perfectly black parallel planes 1.2 by 1.2mare separated by a distance of 1.2 m. One plane is maintained at 800 K and the other at 500 K. The plates are located in a large room whose walls are at 300 K. What is the net heat transfer between the planes?arrow_forwardA 3-in-diameter cylindrical wire is coated in 3 inches of polyethylene insulation. The wire can be modeled as a grey body with an emissivity of .85. Due to the electrical resistance, the wire is at a temperature of 300 degrees Celsius. The insulation is also a great body with an emissivity of .95, at a temperature of 40 degrees Celsius. (Assume F12=1). What is the heat flux (W/m^2) of the energy going from the wire to the insulation?arrow_forward! Required information Irradiation on a semi-transparent medium is at a rate of 640 W/m². If 160 W/m² of the irradiation is reflected from the medium and 130 W/m² is transmitted through the medium, Determine the absorptivity of the medium. The absorptivity of the medium is 0.75 Xarrow_forward
- 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 thewhich the cube emits radiation energy, in W, and b) the spectral emission power of bodyblack at a wavelength of 4 mm.As =?Eb =?Ebλ =?arrow_forwardThe parameter that measures how closely a surface approximates a blackbody is called Reflectivity Transmissivity Emmisivity Absorptivityarrow_forwardI need the answer as soon as possiblearrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University Press
Mechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSON
Thermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education 
Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEY
Mechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage Learning
Engineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY
Elements Of Electromagnetics
Mechanical Engineering
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Oxford University Press
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:9780134319650
Author:Russell C. Hibbeler
Publisher:PEARSON
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:9781259822674
Author:Yunus A. Cengel Dr., Michael A. Boles
Publisher:McGraw-Hill Education
Control Systems Engineering
Mechanical Engineering
ISBN:9781118170519
Author:Norman S. Nise
Publisher:WILEY
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:9781337093347
Author:Barry J. Goodno, James M. Gere
Publisher:Cengage Learning
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:9781118807330
Author:James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:WILEY