Which circuit would thre light bulbs stay lit if you unscrewed one of the four?

Question

I saw this question on a test and I am having a hard time answering it. There was a picture and I became totally confused. Please help?

Answer 1

Parallel circuit.

If the four lights were in series, like X---X---X---X, removing a bulb would result in X---O---X---X. That O gap in the circuit would cause the current from left to right to stop and all the X remaining light bulbs would go out. Current is what makes bulbs glow, not voltage.

But for a parallel circuit, we'd have

|--X--|
|--O--|
|--X--|
|--X--|

Thus, current from left to right for the four connected wires would continue across the remaining X bulbs even though O had been removed. That is, only the bit of wire containing the O would be without current.

Think of the wires as water pipes and the current of electricity as water flowing in the pipes. If you have a series of valves in a single pipe and you shut one off, the water ceases to flow through that pipe...period...even though the other valves are open. But if you have parallel pipes and shut one valve off, the water just goes around that one and through the other valves that stay open. And that's what electrical current does.

Answer 2

The circuit where all 4 bulbs are wired in parallel. If the current has to go through one bulb to get to another, then that is not a parallel connection, that is a series connection, and unscrewing one bulb in a series connection will prevent other bulbs in series with it from getting any voltage.

Answer 3

Where is the picture?