In a home ground floor and 1st floor.In 1st floor 3 bulbs are there and in ground floor three switches.Only once we have to go to 1st floor but we should be known which switch is for which bulb

• ON the first switch then wait for sometime and switch it off .
  then ON the second one keeping the third and first closed.
  go to first floor the bulb which is lit is for the switch second , the hot one among the two off bulb is for the first and the other for the third.
  P.S. be careful while touching the bulb
• 10 years agoHelpfull: Yes(39) No(1)
• First we will press the first switch and keep it ON for 2 minutes and then press it OFF. Then we put ON the second switch and move on to the first floor. If the bulb is lighten up then the switch id for the second one and if not then we touch up the bulb and check which one is heated up. This will let us know that which bulb was lighten up before and the third bulb is normally OFF as no switch was pressed for it.
• 10 years agoHelpfull: Yes(1) No(0)
• incomplete ques!!
• 10 years agoHelpfull: Yes(0) No(4)
• ON the first switch then wait for sometime and switch it off .
  then ON the second one keeping the third and first closed.
  go to first floor the bulb which is lit is for the switch second , the hot one among the two off bulb is for the first and the other for the third.
• 8 years agoHelpfull: Yes(0) No(0)