Final answer:
The brightness of the bulb will remain the same when the switch is closed on an ideal battery with no internal resistance.
Step-by-step explanation:
When the switch is closed and the battery has an ideal situation with no internal resistance, the brightness of the bulb will remain the same. This is because an ideal battery maintains a constant voltage across its terminals, regardless of the current flowing through it. The brightness of the bulb is directly proportional to the current flowing through it, so if the current remains constant, the brightness will also remain constant.