Wait, just to clarify, you're trying to do an imbue effect?
Basically what I want is to be able to change an object by hitting it with a spell, so that it becomes "powered", it becomes something I can use for different things.
I think what I want is going to be either impossible or too difficult to be worth doing, so I'm going to alter my aims a bit.
And if the sphere takes fire damage -> activate torch on fire, or whatever it is you wanted to do.
This sounds more reasonable, and is a pretty cool idea. I think Crafthold could benefit from lights/door/machines that are activated by switches that you have to hurl a spell at.