The 3.8 V battery of a smartphone experiences an increase in its internal resistance due to exposure to extreme temperatures. Consequently, the battery's efficiency decreases, resulting in a shorter life. The cell phone can be connected to an external power source to charge its internal battery. Assume that the smartphone battery and the external power source are connected to a 0.75 Ω resistor, as illustrated in the figure below. Determine the current that passes through the 0.75 Ω resistor if the switch is closed.