As the very first rudiment of climatology, estimate the temperature of Earth. Assume it is a perfect sphere and its temperature is uniform. Ignore the greenhouse effect. Thermal radiation from the Sun has an intensity (the “solar constant” S) of about 1370 W/m2 at the radius of Earth’s orbit. (a) Assuming the Sun’s rays are parallel, what area must S be multiplied by to get the total radiation intercepted by Earth? It will be easiest to answer in terms of Earth’s radius, R.

As the very first rudiment of climatology, estimate the temperature of Earth. Assume it is a perfect sphere and its temperature is uniform. Ignore the greenhouse effect. Thermal radiation from the Sun has an intensity (the “solar constant” S) of about 1370 W/m2 at the radius of Earth’s orbit. (a) Assuming the Sun’s rays are parallel, what area must S be multiplied by to get the total radiation intercepted by Earth? It will be easiest to answer in terms of Earth’s radius, R.

Physics for Scientists and Engineers: Foundations and Connections

1st Edition

ISBN:9781133939146

Author:Katz, Debora M.

Publisher:Katz, Debora M.

Chapter21: Heat And The First Law Of Thermodynamics

Section: Chapter Questions

Problem 61PQ

See similar textbooks

Similar questions

As a rough approximation, the human body may be considered to be a cylinder of length L=2.0m and circumference C=0.8m. (To simplify things, ignore the circular top and bottom of the cylinder, and just consider the cylindrical sides.) If the emissivity of skin is taken to be e=0.6, and the surface temperature is taken to be T=30∘C, how much thermal power P does the human body radiate?
Suppose a person is covered head to foot by wool clothing with an average thickness of d = 1.95 cm and is transferring energy by conduction through the clothing at the rate of Q / Δt = 45 W. What is the temperature difference, in terms of the quantities given in the problem statement, across the clothing? Denote the surface area of the wool by A and the thermal conductivity by k.
A 2-m * 1.5-m section of wall of an industrial furnaceburning natural gas is not insulated, and the temperatureat the outer surface of this section is measured to be 80°C.The temperature of the furnace room is 30°C, and the combinedconvection and radiation heat transfer coefficient at thesurface of the outer furnace is 10 W/m2·K. It is proposed toinsulate this section of the furnace wall with glass wool insulation(k = 0.038 W/m·K) in order to reduce the heat lossby 90 percent. Assuming the outer surface temperature ofthe metal section still remains at about 110°C, determine thethickness of the insulation that needs to be used.The furnace operates continuously and has an efficiency of78 percent. The price of the natural gas is $1.10/therm (1 therm =105,500 kJ of energy content). If the installation of the insulationwill cost $250 for materials and labor, determine how long it willtake for the insulation to pay for itself from the energy it saves.
The entire surface of Earth receives an average of 430 W/m2 of heat flux from the Sun through radiation. What would be the temperature of Earths surface if it radiated like a black body? (The solution is 22°C)
During heavy exercise, the body pumps 2.00 L of blood per minute to the surface, where it is cooled by 2.00C. What is the rate of heat transfer from this forced convection alone, assuming blood has the same specific heat as water and its density is 1050 kg/m3 ?
Two concentric spheres of diameters 15 cm and 25 cm are separated by air at 1 atm pressure. The surface temperatures of the two spheres enclosing the air are T1 = 350 K and T2 = 275 K, respectively. Determine the rate of heat transfer from the inner sphere to the outer sphere by natural convection.
A body whose surface area is 0.2 m2, emissivity is 0.8, and temperature is 100°C is placed in a large, evacuated chamber whose walls are at 25°C. What is the rate at which radiation is emitted by the surface, in W? What is the net rate at which radiation is exchanged between the surface and the chamber walls, in W?
A sphere of radius 0.500 m, temperature 25.7o C, and emissivity 0.915 is isolated in an environment of temperature 77.0o C. At what rate does the sphere emit thermal radiation? At what rate does the sphere absorb thermal radiation? What is the sphere's net rate of energy exchange?
The intensity of solar radiation reaching the Earth is 1,340 W/m2. If the sun has a radius of 7.000 × 108 m, is a perfect radiator and is located 1.500 × 1011 m from the Earth, then what is the temperature of the sun?
Consider steady heat transfer between two large parallel plates at constant temperatures of T1 = 290 K and T2 = 150 K that are L = 2 cm apart. Assuming the surfaces to be black (emissivity « = 1), determine the rate of heat transfer between the plates per unit surface area assuming the gap between the plates is (a) filled with atmospheric air, (b) evacuated, (c) filled with fiberglass insulation, and (d) filled with superinsulation having an apparent thermal conductivity of 0.00015 W/m·K.
An aluminum wire is wrapped in rubber insulation. Both are subject to thermal expansion, with the following coefficients of linear expansion: alphaa=24· 10−6 1/C and alphar=8· 10−5 1/C . If the wire and insulation are the same length of 1.85m at a temperature of20.00°C, what is the difference in length (in MILLIMETERS) between the copper wire and the rubber insulation when heated up to a temperature of 189.00°C? Express a magnitude only (no negatives!). ______mm (MILLIMETERS!)
The outer surface of a spacecraft in space has an emissivity of 0.6 and an absorptivity of 0.2 for solar radiation. If solar radiation is incident on the spacecraft at a rate of 1000W/m2, determine the surface temperature of the spacecraft when the radiation emitted equals the solar energy absorbed.