Along the perpendicular axis that bisects the line between these two charges E Eg =E,COS0+E_COS0 B E.-B.= q E πe.6+P/4月 cos0= 2F2+1P14 -q 1 q l EB =2E COS0=- 4πe.r2+P/42 r>>I E= gl 46。r 4π6r Along the perpendicular axis that bisects the line between these two charges  -q l q r EB B E+ E- EB  E cos  E cos   2 2 2 4 r l 4 q E E o        2 4 cos 2 2 r l l      3 2 2 2 4 4 2 cos r l ql E E o B        r>>l 3 3 4 4 r p r q l E o o B     