3.Field Lines:dr==2cose=2cote rde E sine dr=2cotede=Inr=2In(sine)+C r=ro sin2 0 o=r(9=2 2 中=0 4 (a) q 1 4nEod 6 Figure 44.2 (a)Croso section of equipotentials and lines of electric field intensity for the two charges of Figure 4.4.1.(b)Limit in which pair of charges form a dipole at the origin. Courtesy of Hermann A.Haus and James R.Melcher.Used with permission. 6.641,Electromagnetic Fields,Forces,and Motion Lecture 5 Prof.Markus Zahn Page 10 of 116.641, Electromagnetic Fields, Forces, and Motion Lecture 5 Prof. Markus Zahn Page 10 of 11 3. Field Lines: dr 2 cos Er 2 cot rd E sin θ θ == = θ θ θ ( ) dr 2 cot d lnr 2ln sin C r = θ θ⇒ = θ + 2 0 r r sin = θ r r 0 ( 2) = θ= π Courtesy of Hermann A. Haus and James R. Melcher. Used with permission. 0 q 1 4 d = πε