1. The problem statement, all variables and given/known data A battery has an emf E and internal resistance r. A variable resistor R is connected across the terminals of the battery. Find the values of R such that (a) the potential difference across the terminals is a maximum; (b) the current in the circuit is a maximum; (c) the power delivered to the resistor is a maximum. 2. Relevant equations I=E/(R+r) 3. The attempt at a solution Im not sure if question (a) is talking about max voltage we can run on the circuit, or is just talking about the EMF in which case it never changes. b) I assume when R=0 we get max current, no resistant means max current. C) Max Power transfer theorem says when R=r we get max power. Any help with a) greatly appreciated.