Light Bulbs

There are 3 light bulbs in a room. There are 3 switches in another room. You cannot see into either room from the outside and assume that once you enter the room, the door is closed. Also, assume that all lights and switches are perfectly functional. You can only enter each room once. How can you find out which switch operates which light?
Submitted  2/10/2000 8:43:14 PM
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