238 



ADVANCED ELECTRICITY AND MAGNETISM. 



voltage is everywhere zero to the instant when current is every- 

 where zero. At the instant which is represented by the curve e$ 

 (when electric field is distributed as shown in the diagram 



Nt N* Ni N e Ni N 



Jfi 



magnetic field inward 



Ne 



magnetic field outward 



Fig. 175. 

 Ni N e 



magnetic field outward magnetic field inward 



Fig. 177. 

 Ife Ifi Ne 1ft 



CD C'D'} current starts to flow at each point in the transmission 

 line in directions opposite to the currents shown in the diagram 

 ABA'B', and these currents increase until they reach values 

 represented by the ordinates of the curve ^'9 at which instant 



