1. The problem statement, all variables and given/known data A battery with emf, [tex]E[/tex], and internal resistance, r, is connected to a variable resistance, R, at points X and Y, as shown above on the left. Varying R changes, both the current I and the terminal voltage Vxy. The quantities I and Vxy are measured for several values of R and the data are plotted in a graph, as shown above the right. (a) Determine the emf of the battery. (b) Determine the internal resistance of the battery. (c) Determine the value of the Resistance that will produce a current I of 3 amperes. (d) Determine the maximum current that the batter can produce. 2. Relevant equations V=IR 3. The attempt at a solution I attempted to use Kirchhoff's loop rule. I'm not sure if I should be using it or not. (a) [tex]E[/tex] - Ir - R = 0 [tex]E[/tex] = Ir + R (b) r = ([tex]E[/tex] - R)/I (c) V = IR R = V/I = 3V/3A = 1 ohms (d) I have no idea what to do. Help?