There are three cieling mounted, incandecent light fixtures in the hallway of a testing laboratory. The cieling is eight feet above finished floor.
There are three single pole switches for these fixtures in a room along this hallway.
The room with the switches has a drywall cieling at eight feet and no windows.
YOU CANNOT SEE THE FIXTURES FROM THE SWITCH LOCATION.
You are allowed to enter the room one time. You can stay in there as long as you want but,once you leave the room, you can't go back in there.
You have an six foot step ladder and a voltage tester.
How do you tell which switch controls which light fixture?