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The effect of urbanization on plant growth. A study published in July 2004 indicated that temperature increases in urban areas in the eastern United States are causing plants to bud up to 7 days early compared with plants in rural areas just a few miles away, thereby disrupting biological cycles. Average temperatures in the urban areas were up to 3.5 C° higher than in the rural areas. By what percent will the
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- The following heat transfer formula quantifies the radiation emitted from the Sun: P = eoA(T4 – T?) Equation 5 where: P= radiated power (Watts) e = emissivity (=1 for ideal radiator; unitless) o = Stefan-Boltzmann constant = 5.67x10-8 W/m2-K+ A = radiating area (m²) T= temperature of radiator (Kelvin) Tc = temperature of surroundings (Kelvin) Q3 Using the following values, together with equation 5, calculate the power emitted by the Sun. sun's surface temperature = 5780 K temperature of the environment that the Sun is located in = 4 K emissivity of the Sun = 1 radius of the Sun = 695,700,000 m Stephen-Boltzmann constant o = 5.67 x 10-8 W/m2-K4 Show your work below-you may use the equation editor or insert a picture of your handwritten work.arrow_forwardThe amount of radiant energy emitted by a surface is given by q = ɛ0 AT+ where q represents the rate of thermal energy (per unit time) emitted by the surface in watts; e = the emissivity of the surface 0<ɛ<1 and is unitless o = Stefan-Boltzman constant (o = 5.67×10% ) A represents the area of the surface in m² Ty = surface temperature of the object expressed in kelvin What are the appropriate units for o if the equation is to be homogeneous in units?arrow_forwardIn a warm room a naked resting person has a skin temperature of 33°C if the room temperature is 29° C, what is the body surface area if the rate of heat loss due to convection is 43watt and the convection constant K =7.1 watt /m?.K Choose the right answer: 1.8m? 1.5m2 O 1.7m2arrow_forward
- An average car consumes about 5 L of gasoline a day, and the capacity of the fuel tank of a car is about 50 L. Therefore, a car needs to be refueled once every 10 days. Also, the density of gasoline ranges from 0.68 to 0.78 kg/L, and its lower heating value is about 44,000 kJ/kg (i.e., 44,000 kJ of heat is released when 1 kg of gasoline is completely burned). Suppose all the problems associated with the radioactivity and waste disposal of nuclear fuels are resolved, and a car is to be powered by U-235. If a new car comes equipped with 0.1-kg of the nuclear fuel U-235, determine if this car will ever need refueling under average driving conditionsarrow_forwardA human body has a temperature of 300 If its total surface area is 1.2 m2, what is the net rate of heat loss from the body by radiation considering surrounding temperature to be 240C? Note: emissivity of human skin = 0.95.arrow_forwardSuppose a person is covered head to foot by wool clothing with average thickness of 2.25 cm and is transferring energy of 3000 joules by conduction through the clothing for 2 minutes. What is the temperature difference across the clothing, given the surface area is 1.2m2? (Given: Thermal conductivity of wool is 0.04 W/mK) a) The difference in temperature?arrow_forward
- Homes are often insulated with fiberglass insulation in their walls and ceiling. The thermal conductivity of fiberglass is 0.040 W/m·K. Suppose that the total surface area of the walls and roof of a windowless house is 370 m2 and that the thickness of the insulation is 10 cm. At what rate does heat leave thehouse on a day when the outside temperature is 30°C colder than the inside temperature?arrow_forwardThe amount of heat per second conducted from the blood capillaries beneath the skin to the surface is 230 J/s. The energy is transferred a distance of 1.8 × 10-3 m through a body whose surface area is 1.7 m2. Assuming that the thermal conductivity is that of body fat, determine the temperature difference between the capillaries and the surface of the skin.arrow_forwardThe next four questions use this description. Our Sun has a peak emission wavelength of about 500 nm and a radius of about 700,000 km. Your dark-adapted eye has a pupil diameter of about 7 mm and can detect light intensity down to about 1.5 x 10-11 W/m². Assume the emissivity of the Sun is equal to 1. First, given these numbers, what is the surface temperature of the Sun in Kelvin to 3 significant digits? 5,796arrow_forward
- A ceiling area of 100 square meters consisting of four materials. The thermal insulation value of these materials from top to bottom is (0.6, 50, 0.7 and 0.45) square meters per watt per degree, respectively. If the external temperature is 5 degrees and the internal temperature is 20 degrees, what What is the speed of heat transfer through the wall?arrow_forwardWhat is the rate of heat transfer by radiation from the skin of a person standing in a dark room whose ambient temperature is 22 °C ? The person has a normal skin temperature of 33 °C and a surface area of 1.50 m².The emissivity of skin is 0.97 in the infrared, the part of the spectrum where the radiation takes place.arrow_forwardConsider a flat-plate solar collector placed on the roof of a house. The temperatures at the inner and outer surfaces of the glass cover are measured to be 33°C and 31°C, respectively. The glass cover has a surface area of 2.5 m2, a thickness of 0.6 cm, and a thermal conductivity of 0.7 W/m·K. Heat is lost from the outer surface of the cover by convection and radiation with a convection heat transfer coefficient of 10 W/m2·K and an ambient temperature of 15°C. Determine the fraction of heat lost from the glass cover by radiation.arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning