( ( ( The lines ) ( of ( the ( electric field ) ) ) ) ( ( are ( perpendicular ( to ( the ( equipotential lines ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNS lines)) (PP (IN of) (NP (DT the) (JJ electric) (NN field)))) (VP (VBP are) (ADJP (JJ perpendicular) (PP (TO to) (NP (DT the) (JJ equipotential) (NNS lines))))) (. .)))
The lines of the electric field are perpendicular to the equipotential lines.
(ROOT (S (SBAR (IN Since) (S (NP (DT the) (JJ electric) (NN field) (NNS lines)) (VP (VBP point) (ADVP (RB radially)) (ADVP (RB away) (PP (IN from) (NP (DT the) (NN charge))))))) (, ,) (NP (PRP they)) (VP (VBP are) (ADJP (JJ perpendicular) (S (VP (TO to) (VP (VB equipotential) (NP (NNS lines))))))) (. .)))