消える and 消す: lights, writing, and disappearing traces
Distinguish lights going out and writing disappearing from the actions causing them, and check the object before using 消す for a device.
A light goes out
突然、廊下の電気が消えました。 says that the hallway light suddenly went out. 消える, read きえる, does not itself identify a power outage or someone using the switch.
寝る前に電気を消しました。 means that the speaker turned off the light before bed. 消す, read けす, becomes 消して; 電気を消してください requests turning the light off.
A tool for erasing writing
消しゴムで鉛筆の線を消しました。 says that someone erased pencil lines with an eraser. 消す applies to removing visible marks as well as turning lights off.
何度消しても、線が少し残っています。 means that some of the line remains despite repeated erasing. Performing the action 消す does not guarantee that every trace is gone.
Match the verb to what stops
テレビを消して、話を聞いてください。 asks someone to turn off the television and listen. It does not ask them to remove the television itself.
車のエンジンを止めました。 says that someone stopped a car engine. Learn verb–noun combinations rather than applying 消す to every object described with English “turn off.”
Does 廊下の電気が消えました identify who switched the light off?
Show the answer and why
No. It reports only that the hallway light went out. To describe a person's action, name that person as the subject and use 電気を消しました.