chapter 4 swihart
problems: 7,8

#7
unit convert: erg= g (cm/s)^2 = 10^-3 (10^-2)^2 Kg (m/s)^2 = 10^-7 J
erg/cm^2/s=10^-7 J/(10-2 m)^2/s=10^-3 W/m^2
Flux=1.4e3 W/m^2

.5*.05*Flux*Area=100
? 100/.05/1.4e3/.5
    2.857142857142857    

#8
total energy content of Sun from example 4.5-2: 2.5E48 erg = 2.5E41 J
4 pi Rsun^2 signa T^4 = rate of energy loss

? 2.5E41/(4*pi*Rsun^2*sigma*5800^4)
    640564690016863.1    
? res/year
    20298701.10992619    

number density of STP air (often called Loschmidt constant) =  2.6867805E25
20286794 T^3 = 2.6867805E25

? (2.6867805E25/20286794)^(1/3)
    1098178.464364343    
? atm
    101325.0000000000    
!4 sigma/(3c) * T^4 = atm
? (atm*3*c/(4*sigma))^.25
    141578.3519459439