Light counters almost all meta powers, but her weaknesses are non meta based.(and shes slower than a normal person) You probably wont kill her short of throwing her in a big particle collider/accelrator or a quantum singularity so containment is the name of the game with her, and its actually pretty easy if you watch cartoons. 

Actually its probably easier to hold her than it is a normal person if you know what your doing. And it'll also annoy her to no end. xD