A concrete ball of radius 2.32 m and emissivity 0.620 is heated to 123°C. (a) Convert the given temperature to Kelvin. (Enter your answer to at least three significant figures.) ?K (b) What is the surface area (in m2) of the ball? ?m2 (c) If the ambient temperature is 26.0°C, what net power (in W) does the ball radiate? ?W

A concrete ball of radius 2.32 m and emissivity 0.620 is heated to 123°C. (a) Convert the given temperature to Kelvin. (Enter your answer to at least three significant figures.) ?K (b) What is the surface area (in m2) of the ball? ?m2 (c) If the ambient temperature is 26.0°C, what net power (in W) does the ball radiate? ?W

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.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.28P: 1.28 The sun has a radius of and approximates a blackbody with a surface temperature of about 5800...

See similar textbooks

Similar questions

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.
1.13 If the outer air temperature in Problem is –2°C, calculate the convection heat transfer coefficient between the outer surface of the window and the air, assuming radiation is negligible.
A spherical communications satellite, 2 m in diameter, is placed in orbit around the earth. The satellite generates 1000 W of internal power from a small nuclear generator. If the surface of the satellite has an emittance of 0.3, and is shaded from solar radiation by the earth, estimate its surface temperature.
A geodesic dome constructed with an aluminum frameworkis a nearly perfect hemisphere; its diameter measures 55.0 m on a winterday at a temperature of -15°C. How much more interior space does thedome have in the summer, when the temperature is 35°C?
What is the solar radiation on a horizontal surface in the absence of the atmosphere at latitude 36° N on March 15 for one day?
An astronaut performing an extra-vehicular activity(space walk) shaded from the Sun is wearing a spacesuitthat can be approximated as perfectly white (e = 0) exceptfor a 5 cm × 8 cm patch in the form of the astronaut’snational flag. The patch has emissivity 0.300. The spacesuitunder the patch is 0.500 cm thick, with a thermalconductivity k = 0.0600 W/m °C , and its inner surface isat a temperature of 20.0 °C . What is the temperature of thepatch, and what is the rate of heat loss through it? Assumethe patch is so thin that its outer surface is at the sametemperature as the outer surface of the spacesuit under it.Also assume the temperature of outer space is 0 K. You willget an equation that is very hard to solve in closed form,so you can solve it numerically with a graphing calculator,with software, or even by trial and error with a calculator.
A 30 x 30 cm door in a brick kiln is at a distance of 3.5 m from a wall 12 m wide and 5 m high. The door is so located that a normal from the center of the door strikes the wall midway from the ends and 1.5 m above the floor. The opening into the kiln may be considered a black body; the wall is painted flat paint (Ɛ = 0.46). The temperature inside the kiln is 1 400 C and the wall temperature is 60 C. Determine (a) the configuration factor F12 and (b) the net radiant heat exchange between the opening and the wall when the fire door is open?
A spherical interplanetary probe of 0.5-m diameter contains electronics that dissipate 150 W. If the probe surface has an emissivity of 0.8 and the probe does not receive radiation from other surfaces, as, for example, from the sun, what is its surface temperature?
An electric hot plate is placed in a room which is maintained at a temperature of 297 K. The plate is maintained at a temperature of 403 K and has an emissivity of 0.8. If the plate surface resembles a circular disc of diameter 250 mm, electrical power consumed by the hot plate will be?
Light 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 +-14.4from 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?
A long, horizontal, cylindrical steel reactor, 1 m in diameter, has a surface temperature of 300ºC. The emissivity of the steel is 0.6, and the heat transfer coefficient for natural convection is 5 W m−2 K−1 . Heat is lost by convection to the air at 15ºC, and also by radiation to the surroundings, which can be considered to be a black body at 15ºC. a) Calculate the total heat loss per metre length of the reactor, and the proportions lost by convection and radiation. b) The reactor is then insulated with a thin layer of insulation material to reduce the total heat loss to one-tenth of its original value. This causes the surface temperature of the steel to rise to 400ºC. The thermal conductivity of the insulation is 0.01 W m−1 K−1 , and its surface emissivity is 0.2. Show that the resulting surface temperature of the insulation is about 89ºC, and calculate the thickness of insulation required, stating any assumptions made. can you solve part b please?
A long, horizontal, cylindrical steel reactor, 1 m in diameter, has a surface temperature of 300ºC. The emissivity of the steel is 0.6, and the heat transfer coefficient for natural convection is 5 W m−2 K−1 . Heat is lost by convection to the air at 15ºC, and also by radiation to the surroundings, which can be considered to be a black body at 15ºC. a) Calculate the total heat loss per metre length of the reactor, and the proportions lost by convection and radiation b) The reactor is then insulated with a thin layer of insulation material to reduce the total heat loss to one-tenth of its original value. This causes the surface temperature of the steel to rise to 400ºC. The thermal conductivity of the insulation is 0.01 W m−1 K−1 , and its surface emissivity is 0.2. Show that the resulting surface temperature of the insulation is about 89ºC, and calculate the thickness of insulation required, stating any assumptions made. Specifically need help with part b