Fact 1: Aswitch is used to start the flow of current in an electrical circuit.

Fact 2: Electrical power including lights etc can then be switched on.

Given the two facts above, answer the question "what are on when there is flow of current in an electrical circuit" with the following options: 
- energy
 - lights
 - engine
 - cycles
 - brakes
 - waves
 - water
 - Vibrates


 

  lights       