2l6 



ADVANCED ELECTRICITY AND MAGNETISM. 



2b 



a + b 



20, 

 a + b 



E 



(21) 



(22) 



Reflection at a place where a line branches. The doubled 

 arrow in Fig. 152 represents a wave which has been partly 



Fig. 152. 



Showing a rectangular wave pulse partly reflected and partly transmitted at a 

 point where an air line branches. 



reflected at a branch point in a line, and the two short arrows 

 EJt represent the waves which have entered the branches. The 

 two branches are both assumed to be like the original line for 

 the sake of simplicity. In this case we have: 



E + E r = E t (23) 



/ + I r = 2l t (24) 



Er 

 I, 



= a 



E, 



77=+ 



(25) 

 (26) 



(27) 



from which we get E, = -E/3 and I, = +//3; and E, = + \E 



