Outside a room are 3 switches, each controlling one of 3 old-style bulbs inside the room (

Outside a room are 3 switches, each controlling one of 3 old-style bulbs inside the room (which get hot when lit). You can enter the room only once. Divya thinks that without going in repeatedly, it is impossible to figure out which switch controls which bulb. Her friend says there is a way. Who is right?