Q. How tube lights function?

Answer

Tube lights contain ballast and a starter, which are essential components amongst the others. When power is switched on, full voltage is supplied through the ballast and the starter. Initially, no lumen output can be seen in the lamp. At full voltage supply, the glow discharge happens in the starter and after that the inert gas inside the starter is ionized that result in heating of the bimetallic strip. Moments later the discharge of mercury atoms result in emitting ultra violet radiation that consequently activates the phosphor coated glass to radiate observable light.