engineering intelligence MCQ #266

Three switches are connected to three light bulbs in a room. Each switch corresponds to one light bulb, but none of them are labelled. How can you figure out which switch corresponds to which light bulb by only entering the room once?

engineering intelligence MCQ #266

  1. Question 1

    Q1. Three switches are connected to three light bulbs in a room. Each switch corresponds to one light bulb, but none of them are labelled. How can you figure out which switch corresponds to which light bulb by only entering the room once?

    • A) Turn two switches on for different durations
    • B) Turn one switch on, then turn it off and turn another on
    • C) Turn all switches on, then turn one off
    • D) Turn one switch on, go into the room, and observe

    Answer: Turn two switches on for different durations

    Explanation: Turn switch 1 to ON for 5 minutes. Turn switch 2 to ON. Now go into the room. The hot bulb corresponds to switch 1, the ON bulb to switch 2, and the remaining to switch 3.