Answer :
Hello I hope you are having a great day :)
Your question: When a light switch is turned on, the light comes on immediately because....
The answer is: the electrons in the wire are instantly "pushed" by a voltage difference making the the light switch on.
Hopefully that helps you :)
The Energy and Electric is in the air already so it will always light up just like a candle when it burns out you can light the smoke and it will start back