2. * a. A surface at 27 °C emits radiation at a rate of 100 W. At what rate does an identical surface at 54 °C emit radiation? b. Determine the wavelength of the maximum amount of radiation emitted by each surface.

The emissivity of the human skin is 97.0 percent. Use 35.0 °C for the skin temperature and approximate the human body by a rectangular block with a height of 1.77 m, a width of 33.0 cm and a length of 29.5 cm.   1. Calculate the power emitted by the human body.   2. What is the wavelength of the peak in the spectral distribution for this temperature?   3. Fortunately our environment radiates too. The human body absorbs this radiation with an absorbance of 97.0 percent, so we don't lose our internal energy so quickly. How much power do we absorb when we are in a room where the temperature is 26.0 °C?   4. How much energy does our body lose in one second?   Please answer all four parts

2. Determine the heat capacity of pure solid aluminum as a function of the temperature, using the Einstein and the Debye models.

1. When the sun is directly overhead, the thermal energy incident upon the earth is about 1.4 × 106 ergs- cm-2-sec-¹. The diameter of the sun is about 1.6 × 10¹¹cm, and the distance from the sun to the earth is about 1.3 × 10¹3 cm. Assuming the that the sun radiates like a black body, use the expression I = σeT4 to estimate its surface temperature. 2. Integrate the expression 8πhc² 1 15 exphc/kXT –1 over all λ, and show that the temperature dependence of the result is T4. I(x) dx -dλ

Two large parallel plates are maintained at 700 and 300 K respectively. The hotter plate has an emissivity of 0.9 and the colder one 0.1. Calculate the net radiation heat transfer between the plates. Lütfen birini seçin a.1031 W/m b.1301 W W/m c.100 W/m d.1514,08 W/m 2. e.1299 W/m

C 6. For solar collectors, what combination of surface characteristics is required? b. High absorptivity and high reflectivity High absorptivity and high emissivity High emissivity and low absorptivity d. High absorptivity and low emissivity c.

5. Calculate the temperature of the solar surface if the radiant intensity at the sun's surface is 63 MW/m². Stefan-Boltzmann constant o = 5.67 x 10-8 W/m²/K4 6. A 3.0 g bullet moving at 120 m/s on striking a 50 g block of wood is arrested within the block. Calculate the rise of temperature of the bullet if (a) the block is fixed; (b) the block is free to move. The specific heat of lead is 0.031 cal/g °C.

Which of the following is NOT an example of a real-life example or application of radiation? A thermos will sometimes have a vacuum layer with no air or other material inside. People who fall into icy water are given shiny, reflective blankets. It's warmer when the lights are on in your home than when they're off. A person Sun-bathing. A thermos flask has a mirrored surface.

1. A device called an insolation meter is used to measure the intensity of sunlight. It has an area of 100 cm and registers 7 W. What is the intensity in W/m? V w/m?

The total power radiated per unit area of temperature T is R. If the temperature increases by 4T, what is that new total power radiated per unit area? A. 4R. B. 16R. C. 64R. D. 256R.