( ( ( The ( SI unit ) ) ( of ( electric potential ) ) ) ( ( is ( ( ( ( the volt ) ( -LRB- ( ( in ( honor ( of ( Alessandro Volta ) ) ) ) -RRB- ) ) ) , ) ( which ( is ( why ( ( ( a difference ) ( in ( ( electric potential ) ( between ( two points ) ) ) ) ) ( is ( known ( as voltage ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNP SI) (NN unit)) (PP (IN of) (NP (JJ electric) (NN potential)))) (VP (VBZ is) (NP (NP (NP (DT the) (NN volt)) (PRN (-LRB- -LRB-) (PP (IN in) (NP (NP (NN honor)) (PP (IN of) (NP (NNP Alessandro) (NNP Volta))))) (-RRB- -RRB-))) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (SBAR (WHADVP (WRB why)) (S (NP (NP (DT a) (NN difference)) (PP (IN in) (NP (NP (JJ electric) (NN potential)) (PP (IN between) (NP (CD two) (NNS points)))))) (VP (VBZ is) (VP (VBN known) (PP (IN as) (NP (NN voltage)))))))))))) (. .)))
The SI unit of electric potential is the volt (in honor of Alessandro Volta), which is why a difference in electric potential between two points is known as voltage.
(ROOT (S (NP (NP (DT The) (NN difference)) (PP (IN in) (NP (NP (JJ electric) (JJ potential) (NN energy)) (SBAR (WHNP (WDT which)) (S (VP (VBZ allows) (PP (IN for) (NP (DT an) (JJ electric) (NN charge))) (S (VP (TO to) (VP (VB move) (PP (IN from) (NP (CD one) (NN position))) (PP (TO to) (NP (DT another)))))))))))) (VP (VBZ is) (VP (VBN measured) (PP (IN by) (NP (DT the) (JJ volt) (NN si) (NN unit))))) (. .)))