ELECTROSTATICS 



31 



This is the value of the tension along the lines of force tending 

 to shorten them, and also the value of the pressure at right angles 

 to the lines tending to spread them apart. 



FIG. 23. Stresses in the 

 electrostatic field. 



FIG. 24. 



26. Effects of Introducing Dielectrics of Various Specific In- 

 ductive Capacities into a Uniform Field. (1) Fig. 24 shows a 

 parallel plate condenser with air as dielectric. 



t = distance between plates in centimeters. 

 A = area of each plate in square centimeters. 

 E = difference of potential between plates. 

 ^ = dielectric flux. 



2) = ^r = dielectric flux density. 

 cF = 2) = electrostatic force in the field. 

 Since the force is constant throughout the field, therefore, 



and the electrostatic force or the stress in the air is 



'-! 



