State whether the resistance of filament of a bulb will decrease, remain unchanged or increase when it glows.
Statement 1: It is observed that sometimes an incandescent bulb glows brighter and sometimes it glows dim.
Statement 2: Glowing brighter and dimmer depends on heating effect of current. More current produces more heating effect making the bulb glow brighter and vice-versa.
If LED glows but bulb does not glow while testing a liquid for passage of electric current, it might mean