| I think that the one ohm resistance of the rod does
| not contribute to the current because motional emf
| (voltage causing the current) exists between its end
| points. Otherwise rod's resistance would act as it
| were an internal resistance of a battery and i1 would
| be 250 mA. Note that the effect of the magnetic field
| produced by a current is ignored; it would not be
| significant in this case.
| Ludwik Kowalski
The rod resistance acts the same as the armature resistance in a generator
(in fact, that is what it is). In both cases it must be included as the
internal resistance of an emf device - as you would do with a battery.