Asking the students how the brightness of each bulb changes after connecting a wire
between A and B as shown above, Peter (Ref.1) noticed a lot of confusion among the
students. In general these kind of two-loop circuits in which we have in addition an
induced emf are very confusing for the students. The important point here, as observed by
Romer (Ref. 2), is that the topology of the circuit is very important when there are
induced emfs, unlike the case of ordinary dc circuits, which can be deformed in any
manner, as long as the ordering of the elements remain the same.