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title: "In the circuit shown, three identical lightbulbs labeled \\(A\\), \\(B\\), and \\(C\\), each of resistance \\(R\\), are connected to an ideal battery of potential difference \\(V_0\\). Switch \\(S\\) is initially open. Switch \\(S\\) is then closed. Which choice correctly describes the change in brightness (power dissipated) of bulbs \\(A\\) and \\(B\\) after switch \\(S\\) is closed, and correctly ranks the power dissipated by all three bulbs in this final state?"
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url: "https://nerd-notes.com/ubq/118360/"
date_modified: "2026-08-04T08:09:40+00:00"
---

# In the circuit shown, three identical lightbulbs labeled \(A\), \(B\), and \(C\), each of resistance \(R\), are connected to an ideal battery of potential difference \(V_0\). Switch \(S\) is initially open. Switch \(S\) is then closed. Which choice correctly describes the change in brightness (power dissipated) of bulbs \(A\) and \(B\) after switch \(S\) is closed, and correctly ranks the power dissipated by all three bulbs in this final state?

In the circuit shown, three identical lightbulbs labeled \(A\), \(B\), and \(C\), each of resistance \(R\), are connected to an ideal battery of potential difference \(V_0\). Switch \(S\) is initially open. Switch \(S\) is then closed. Which choice correctly describes the change in brightness (power dissipated) of bulbs \(A\) and \(B\) after switch \(S\) is closed, and correctly ranks the power dissipated by all three bulbs in this final state?

![A schematic of an electric circuit forming a single rectangular layout. On the vertical left side, an ideal battery is shown with its positive terminal at the top, labeled V_0. The top horizontal wire connects to a resistor symbol labeled A. After resistor A, the wire splits at a node into two parallel vertical branches. The left branch contains a resistor symbol labeled B. The right branch contains a resistor symbol labeled C in series with a switch labeled S shown in the open position. Below bulbs B and C, the two parallel branches recombine at a single node on the bottom horizontal wire, which completes the loop back to the negative terminal of the battery. No other labels, lines, text, or components appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1785830980-A7dded.jpg)

- **A.** Bulb A: Decreases | Bulb B: Increases | Power ranking: \(P_A < P_B = P_C\)
- **B.** Bulb A: Increases | Bulb B: Increases | Power ranking: \(P_A = P_B = P_C\)
- **C.** Bulb A: Decreases | Bulb B: Decreases | Power ranking: \(P_A > P_B > P_C\)
- **D.** Bulb A: Increases | Bulb B: Decreases | Power ranking: \(P_A > P_B = P_C\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/118360/*