1. The problem statement, all variables and given/known data if a potentiometer has driver cell and wire AB ,then an unknown emf (emf<driver cell) is balanced at some length L. does the balance point change if internal resistance of driver cell is changed? 2. Relevant equations V= kl K= potential gradient 3. The attempt at a solution if we increase the internal resistance ,the potential drop across wire AB should decrease and so balance point must shift.. But the solution says it will not change.