Ravi answered
Efficiency of bulbs are usually measured in lumen per watt.
So for incandescent bulb efficiency is 15 lumens per watt, it means a 100 watt incandescent bulb efficiency is 1500 lumens.
LED bulb efficiency is 100 lumens per watt now to get 1500 lumens we need 15 watt led bulb. Therefore 15 watt LED is equivalent to 100 watt incandescent bulb.
Pari answered
Incandescent bulb gives 12 lumens/watt.
Fluorescent tubes (commonly known as bar lights) gives 40 lumen/ watt, LED (light emitting diode) gives 129 lumens/ watt theoretically now since we have to achieve 100 lumens/watt, so approximately 12 Volt led can give lumen output equivalent to 100 watt bulb.
