Final answer:
The process of recharging a battery involves using a charger to reverse the direction of current, requiring the charger's voltage output to be higher than the battery's emf.
Step-by-step explanation:
The question appears to be asking about the process of recharging batteries, specifically within the context of a battery charger used for car batteries or batteries for small electrical appliances. When recharging batteries, a charger reverses the normal direction of current through the battery. This is necessary because to recharge, we need to pass a current in the opposite direction to the current the battery supplies during discharge. It's essential that the voltage output of the charger is greater than the electromotive force (emf) of the battery to reverse the current. As a result, the terminal voltage of the battery becomes greater than the emf, described by the formula V = emf - Ir, with I being negative in this recharge scenario.