ELECTROSTATICS 



9 



a distance dr is 



Sdr = 



and the work done in moving the charge from a point of zero 

 potential to PI is 



-HI 



(9) 



FIG. 6. Distribution of potential about a point charge. 



therefore, the potential at a point due to a charge of electricity 

 is equal to the charge in electrostatic units divided by its distance 

 in centimeters from the point. 



15. Potential at a Point Due to a Number of Charges. If 



FIG. 7. Potential due to a number of charges. 



there are several charges qi, q 2 , qs, etc. in the field, the potential 

 at any point is the sum of the potentials due to the separate 

 charges and is 



