ELECTROSTATICS 



33 



= jr tz = drop of potential across (2), 

 A 2 



2) 

 = T^ ^3 = drop of potential across (3) ; 



Glass 



FIG. 25. 



FIG. 26. 



the difference of potential between the plates is 



E = EI ~\- EZ ~|- ^3 



and the dielectric density is 



and the total ftwx. is 



where 



+ ir, + 2s 



# 



A =EP, 



lE q.34, 



3 



+i a +i 8 



is the permeance of the path between the plates. 



