MAGNETISM AND ELECTROMAGNETICS 



67 



The reluctance of the section db consisting of three paths in 

 multiple must be found. The flux 3> passing through it divides 

 into three parts which are inversely proportional to the reluc- 

 tances of the paths, 



therefore, 



and 



co i oo ~r oo 



e)\ z 003 ca 4 



The reluctance of the whole circuit is 



FIG. 56. Energy stored in a magnetic field. 



47. Energy Stored in the Magnetic Field. When a current 

 i c.g.s. units flows in the solenoid, Fig. 56, wound on an iron 

 ring, a flux is produced, 



