( Electromagnetism ( ( is ( ( based ( on ( the facst ) ) ) ( that ( ( -LRB- ( 1 -RRB- ) ) ( ( ( ( ( ( ( an ( electric current ) ) or ) ( a ( changing ( electric field ) ) ) ) ( produces ( a ( magnetic field ) ) ) ) , ) and ) ( ( -LRB- ( 2 -RRB- ) ) ( ( a ( changing ( magnetic field ) ) ) ( produces ( an ( electric field ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Electromagnetism)) (VP (VBZ is) (VP (VBN based) (PP (IN on) (NP (DT the) (NN facst))) (SBAR (IN that) (S (PRN (-LRB- -LRB-) (NP (CD 1)) (-RRB- -RRB-)) (S (NP (NP (DT an) (JJ electric) (NN current)) (CC or) (NP (DT a) (VBG changing) (JJ electric) (NN field))) (VP (VBZ produces) (NP (DT a) (JJ magnetic) (NN field)))) (, ,) (CC and) (S (LST (-LRB- -LRB-) (LS 2) (-RRB- -RRB-)) (NP (DT a) (JJ changing) (JJ magnetic) (NN field)) (VP (VBZ produces) (NP (DT an) (JJ electric) (NN field)))))))) (. .)))
Electromagnetism is based on the facst that (1) an electric current or a changing electric field produces a magnetic field, and (2) a changing magnetic field produces an electric field.
(ROOT (S (NP (NNP Electromagnetism) (NNP magnetism)) (VP (VBZ is) (VP (VBN produced) (PP (IN by) (NP (NN electricity))))) (. .)))