I am learning electricity and quite often see loops that are connected in one node.
This is a simplified example:
But I found many cases, with more elements.
The thing that makes me question their usefulness is that (so far) they have always behaved as independent circuits.
So, I wonder if circuits are ever designed this way in real life and if this concept (two loops connected at one node) has its own name or is used at all with any purpose.
I also wonder what would happen if one of the loops does not have any voltage source in it, like this:
Would current behave as shown in A or in B or a mix of both and why?
Teacher says: "current is smart and always takes the laziest road" (in this case A), but I don't see how that can be a solid reasoning. Maybe with a clear why.