There are three bulbs inside a house of one floor and switches are in different floor. How will you conclude which switches is for the which bulb

 
 
 
Switch on one bulb; keep the switch off for another bulb. This way you can detect two bulb’s switch. To find the third one is the trick. Keep the third switch on for some times and then switch it off so that the temperature gets increased for the third bulb and you can detect the switch.