Refer to the circuit shown below. In this "ideal" circuit, the battery has no internal resistance so that it maintains a constant potential difference between its terminals at points I and 2 regardless of how much current flows through it. Also, the three light bulbs, A, B, and C, are identical.
(a) What happens to the brightness of each of the three bulbs if a wire is connected from the battery terminal at point I to point 4?
(b) What simultaneously happens to the current through point 3?
(c) What simultaneously happens to the potential difference across bulb B?
(d) What simultaneously happens to the potential difference across bulb C?
(e) What simultaneously happens to the potential difference between points 1 and 5? Explain your reasoning.