4. The circuit below shows four identical bulbs connected to an ideal battery, which has negligible internal resistance. Initially, the switch "S" is open. When the switch "S" is closed, does bulb "D" become brighter, dimmer, or stay the same? Justify your answer using appropriate physics concepts (or justify your answer with calculations using your own numbers. For example, assign a resistance to the bulbs, etc.) Figure 1: Circuit with Ideal Battery