If you turn off one light and all the lights go off, what type of circuit is that?

If you turn off one light and all the lights go off, what type of circuit is that?

• A. Parallel circuit
• B. Series circuit
• C. Open circuit
• D. Short circuit

Answer: (B)

In a series circuit, current flows through a single loop and all the lights share the same current. Because of that single path, if one light is turned off in a way that opens the circuit, the path is broken and no current can reach any of the lights. So all of them go dark. That’s why turning off one light causes the entire string to go off in this arrangement. By contrast, in a parallel circuit each light has its own branch from the power source. Turning off one light stops current in that branch but the other branches remain powered, so the other lights stay on. An open circuit means there’s no complete path anywhere, which would turn everything off regardless. A short circuit creates a very low-resistance path and usually triggers protection, not simply turning lights off.

In a series circuit, current flows through a single loop and all the lights share the same current. Because of that single path, if one light is turned off in a way that opens the circuit, the path is broken and no current can reach any of the lights. So all of them go dark. That’s why turning off one light causes the entire string to go off in this arrangement.

By contrast, in a parallel circuit each light has its own branch from the power source. Turning off one light stops current in that branch but the other branches remain powered, so the other lights stay on.

An open circuit means there’s no complete path anywhere, which would turn everything off regardless. A short circuit creates a very low-resistance path and usually triggers protection, not simply turning lights off.