MAGNETIC EFFECTS ON NOISE IN A GERMANIUM FILAMENT 659 



1 - c. r5(-a)(7l) (Jl) 



i^-D*'- 



Thus the match of theory to experiment actually provides information 

 about the relative emissivities of the surfaces. 



When the surfaces are equal, ^i = ^2 = ^; (Ji) = ('^2) and the 

 result 12 simplifies to 



10 log Nh for this case is plotted in figure 2. 



It is interesting to see how Nn for equal surfaces varies for small 

 values of $. 2/$ — coth $/2 is regular at <!> = and varies as — <J>/6 

 there. Hence the initial variation is as 



1 + 



$2 



rYQ-|(-.i))- 



Hence the curve rises or falls initially according as 



^»4('+J)- 



The noise therefore increases initially if 



12 2 xp 

 and falls initially if 



511 



— ->— or ^>6.9 approximately 



lA < 6.9. 



2. Volume Generation. 



At first sight it may seem that if volume generation is considered, so 

 should volume recombination (detailed balancing). This is not neces- 

 sarily so, since we are not dealing with an equilibrium situation here. 



