A battery with an emf of 1.50 V has an internal resistance r. When connected to a resistor R, the terminal voltage is 1.40 V and the current is 0.18 A. What is the value of the external resistor R? What is the internal resistance r of the battery? What is the energy dissipated in the battery's internal resistance in 2.1 minutes? When a second identical battery is added in series and the external resistor is R = 20 Ohms what is the resulting current?