Radiation

Question 1

What is the Emissive Power of a black body?

Answer 1

E = sigma T^4

Question 2

For a black body with given temperature, how do you find the wave length below which 10 percent of the emission is concentrated?

Answer 2

1. Identify the fraction, on the table under F, (interpolate if necessary) and the corresponding lambda T. Divide by T

Question 3

How do you determine the maximum spectral emissive power and corresponding wavelength for that emission for black body?

Answer 3

1. Find max wavelength using Wiens law
2. Third column in table is max emissive power

Question 4

How do you find steady state temperature of the earth?

Answer 4

1. Do energy balance for earth: E^.in = E^.out
2. Edot in = G A
3. Edot out = AE
4. E = sigma T^4

Question 5

How do you set up a radiation resistance Network?

Answer 5

1. Identify Nodes Associated with Radiosity of Each Surface
2. Connect radiosity node using appropriate space resistance. R = (AF)^-1
3. J = sigma T^4