In a mixed circuit, removing a bulb can cause the remaining bulb to brightness change in what way according to the source?

In a mixed circuit, removing a bulb can cause the remaining bulb to brightness change in what way according to the source?

• A. The remaining bulb remains unchanged
• B. The remaining bulb will dim or brighten depending on the arrangement
• C. The remaining bulb will always brighten
• D. The remaining bulb will always dim

Answer: (B)

The important idea is that removing a bulb in a mixed circuit can change how current and voltage are distributed, so the brightness of a remaining bulb can either go up or down depending on how the circuit is wired. If the removed bulb is in the same series path as another bulb, that path loses current, so the remaining bulb in that chain dims or goes out. If the removed bulb was in parallel with others, an ideal voltage source keeps the voltage across the remaining branches the same, so their brightness doesn’t change; but with a real power source that has internal resistance, removing a bulb can slightly raise the voltage across the remaining parallel branches, causing them to brighten. Because a mixed circuit contains both series and parallel relationships, the net effect can be a mix of dimming in some bulbs and brightening in others. So the remaining bulb’s brightness can either dim or brighten depending on the exact arrangement and the source.

The important idea is that removing a bulb in a mixed circuit can change how current and voltage are distributed, so the brightness of a remaining bulb can either go up or down depending on how the circuit is wired. If the removed bulb is in the same series path as another bulb, that path loses current, so the remaining bulb in that chain dims or goes out. If the removed bulb was in parallel with others, an ideal voltage source keeps the voltage across the remaining branches the same, so their brightness doesn’t change; but with a real power source that has internal resistance, removing a bulb can slightly raise the voltage across the remaining parallel branches, causing them to brighten. Because a mixed circuit contains both series and parallel relationships, the net effect can be a mix of dimming in some bulbs and brightening in others. So the remaining bulb’s brightness can either dim or brighten depending on the exact arrangement and the source.