In the circuit shown, the voltage source has an EMF of 12 V, and some internal resistance, r. You connect the circuit as shown, with two equal external resistances R and a switch, to the voltage source and measure the current out of the battery. The total current out of the battery is 0.38 A when the switch is open and 0.72 A when the switch is closed. What is the internal resistance, r? Hint: You have two unknowns, r and R, so you need two INDEPENDENT equations to solve the problem. And you need to use both equations to get the answer. R R 16.7 Ohms O 0.87 Ohms 14.9 Ohms 1.75 Ohms 4.65 Ohms 23.2 Ohms O 46.5 Ohms 31.6 Ohms