( ( A laser ) ( ( ( emits ( concentrated energy ) ) ( in ( ( the form ) ( of ( a ( light beam ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN laser)) (VP (VBZ emits) (NP (JJ concentrated) (NN energy)) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (NP (DT a) (JJ light) (NN beam)))))) (. .)))
A laser emits concentrated energy in the form of a light beam.
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NNS electrons)) (VP (VB return) (PP (TO to) (NP (DT a) (JJR lower) (NN energy) (NN level)))))) (, ,) (NP (PRP they)) (VP (VBP emit) (NP (NP (DT the) (JJ excess) (NN energy)) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (NP (NN light))))))) (. .)))