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An electric kitchen range has a total wall area of 1.40 m2 and is insulated with a layer of fiberglass 4.00 cm thick. The inside surface of the fiberglass has a temperature of 175°C, and its outside surface is at 35.0°C. The fiberglass has a thermal
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- 500 g of Ice at 0 °C is kept in an insulated cubic box. The length of the box is 30 cm and the thickness of the wall is 0.5 cm. The thermal conductivity of the wall is 0.04 W/mK. If the environment temperature outside the box is 25 °C, Determine (a) the rate of heat loss due to the heat conduction.arrow_forwardWhile swimming, conduction can play a big role in heat loss from the body. The body of one swimmer has a total surface area of 1.80 m2 and an average thickness of 1.60 mm. The skin's thermal conductivity is 0.370 W/m-K. If the water's temperature is 20.0°C, and the blood reaching the inner surface of the skin is at 37.0°C, what is the rate of energy loss for that person through conduction?arrow_forwardThe thermal conductivities of human tissues vary greatly. Fat and skin have conductivities of about 0.20 W/m K and 0.020 W/m · K respectively, while other tissues inslde the body have conductivities of about 0.50 W/m · K. Assume that between the core region of the body and the skin surface lies a skin layer of 1.0 mm, fat layer of 0.50 cm, and 3.2 cm of other tissues. (a) Find the R-factor for each of these layers, and the equivalent R-factor for all layers taken together, retaining two digits. Rakin m2. K/W Rat m2 . K/W Rissue m2. K/W m2- K/W (b) Find the rate of energy loss when the core temperature is 37°C and the exterior temperature is 0°C. Assume that both a protective layer of clothing and an insulating layer of unmoving air are absent, and a body area of 2.0 m.arrow_forward
- A heat conducting rod, 0.90 m long, is made of an aluminum section that is 0.10 m long, and a copper section that is 0.80 m long. Both sections have cross- sectional areas of 0.00040 m2 .The aluminum end is maintained at a temperature of 40° C and the copper end is at 150° C. The thermal conductivity of aluminum is 205 W/m · K and of copper is 385 W/m · K. Steady state has been reached, and no heat is lost through the well-insulated sides of the rod. The temperature of the aluminum-copper junction in the rod is closest toarrow_forward(a) A 1.8 cm thick wooden floor covers a 4.0 m × 5.5 m room. The subfloor is at a temperature of 16.2 ˚C, while the air in the room is at 19.6 ˚C. What is the rate of heat conduction through the floor? The thermal conductivity for wood is 0.2 W / (m K) (b) Seals can cool themselves by using thermal windows, spots on their bodies with a much higher than average surface temperature. Suppose a seal has a thermal window of 0.030m2 at a temperature of 30˚C. If the seal's environment is frosted at -10˚C, what is the net rate of radiation energy loss? Assume an emissivity equal to 0.97. (please show steps, explanation and formulas)arrow_forwardThermography is a technique for measuring radiant heat and detecting variations in surface temperatures that may be medically, environmentally, or militarily meaningful.(a) What is the percent increase in the rate of heat transfer by radiation from a given area at a temperature of 34.0C compared with that at 33.0C, such as on a person’s skin? (b) What is the percent increase in the rate of heat transfer by radiation from a given area at a temperature of 34.0C compared with that at 20.0C, such as for warm and cool automobile hoods?arrow_forward
- Hot water at 85 Degrees Celsius is transferred inside a metal pipe with outer diameter 30mm. A circumferential fin with a rectangular profile is placed on the outer surface of the pipe for cooling. The fin is 80 mm in diameter and 8mm thick. If the heat convection coefficient of the environment outside the pipe = 20 W/m2.°C and the ambient temperature 22 Degree Celsius. Assume that the temperature of the outer surface of the pipe equals the hot water temperature. A. Determine the heat loss by the fin. B. Determine the fin effectiveness. (Thermal conductivity of the fin material 125 W/m.°C)arrow_forwardOne end of an insulated metal rod is maintained at 100.0°C,and the other end is maintained at 0.00°C by an ice–water mixture. Therod is 60.0 cm long and has a cross-sectional area of 1.25 cm2. The heatconducted by the rod melts 8.50 g of ice in 10.0 min. Find the thermalconductivity k of the metal.arrow_forwardThe thermal conductivities of human tissues vary greatly. Fat and skin have conductivities of about 0.20 W/m · K and 0.020 W/m · K respectively, while other tissues inside the body have conductivities of about 0.50 W/m · K. Assume that between the core region of the body and the skin surface lies a skin layer of 1.0 mm, fat layer of 0.50 cm, and 3.2 cm of other tissues. (a) Find the R-factor for each of these layers, and the equivalent R-factor for all layers taken together, retaining two digits. Rskin m2 · K/W Rfat m2 · K/W Rtissue m2 · K/W R m2 · K/W (b) Find the rate of energy loss when the core temperature is 37°C and the exterior temperature is 0°C. Assume that both a protective layer of clothing and an insulating layer of unmoving air are absent, and a body area of 2.0 m2. Warrow_forward
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