In question 5, the inductor is continuously connected to the power supply. As a result, any emf generated by the inductor itself will have to contend with the emf of the power supply as well. Since these two emf's will be of opposite polarity, the emf of the inductor is in essence fighting back against the supply emf. This is why in this case its referred to as "back emf".
Technically I suppose its the same phenomenon, its just in one case it has to contend with the supply emf, which causes a drop and gets it named specifically back emf.