An aluminum sphere of surface area (0.08) is heated to a temperature of (521)K If the rate of heat transfer by radiation from the aluminum sphere is (48)W, then calculate the emissivity of the sphere in square meters? (Stefan's constant o = 5.67 x 108 W/mk4) O a. 2214923651.4775 O b. 0.0008 c. 0.1436 O d. 6.9628

An aluminum sphere of surface area (0.08) is heated to a temperature of (521)K If the rate of heat transfer by radiation from the aluminum sphere is (48)W, then calculate the emissivity of the sphere in square meters? (Stefan's constant o = 5.67 x 108 W/mk4) O a. 2214923651.4775 O b. 0.0008 c. 0.1436 O d. 6.9628

University Physics Volume 2

18th Edition

ISBN:9781938168161

Author:OpenStax

Publisher:OpenStax

Chapter2: The Kinetic Theory Of Gases

Section: Chapter Questions

Problem 77AP: (a) Find the density in SI units of air at a pressure of 1.00 atm and a temperature of 20 , assuming...

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(a) If the partial pressure of water vapor is 8.05 torr, what is the dew point? (760 torr = I atm 101, 325 Pa) (b) On a warn day when the air temperature is 35 and the dew point is 25 , what are the partial of the water in the air and the relative humidity?
(a) Find the density in SI units of air at a pressure of 1.00 atm and a temperature of 20 , assuming that air is 78% N2, 21% O2, and 1% Ar, (b) Find the density of the atmosphere on Venus, assuming that it's 96% CO2 and 4% N2, with a temperature of 737 K and a pressure of 92.0 atm.
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A mercury thermometer still in use for meteorology has a bulb with a volume of 0.780 cm3 and a tube for the mercury to expand into of inside diameter 0.130 mm. (a) Neglecting the thermal expansion of the glass, what is the spacing between marks 1 apart? (b) If the thermometer is made of ordinary glass (not a good idea), what is the spacing?
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?
Super Invar, an alloy of iron and nickel, is a strong material with a very low coefficient of thermal expansion (0.20×× 10^-6 celcius). A 2.5 m -long tabletop made of this alloy is used for sensitive laser measurements where extremely high tolerances are required. A) How much will this alloy table expand along its length if the temperature increases 7.0 C∘? Express your answer to two significant figures and include the appropriate units. B) How much will a 2.5-m-long table made of steel expand along its length if the temperature increases 7.0 C∘? Express your answer to two significant figures and include the appropriate units.
What is the total rate of radiation of energy from a human body withsurface area 1.20 m2 and surface temperature 30°C = 303 K? If thesurroundings are at a temperature of 20°C, what is the net rate of radiativeheat loss from the body? The emissivity of the human body is veryclose to unity, irrespective of skin pigmentation.
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?
A mercury thermometer still in use for meteorologyhas a bulb with a volume of 0.780 cm3and a tube for the mercury to expand into of inside diameter 0.130 mm. (a)Neglecting the thermal expansion of the glass, what is thespacing between marks 1 °C apart? (b) If the thermometeris made of ordinary glass (not a good idea), what is thespacing?
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