Transfer of heat through flowing material

The transfer of heat through flowing material is called CONVECTION.

Convection is one of the methods of heat transfer, the other two methods are conduction and radiation. Convection refers to the process through which heat is transported by mean of a heated fluid. Examples of fluid are water and air. When water is heated, it becomes less dense and rise as a result of increase in its buoyancy; as the heated water rise and moves up, it is immediately displaced by cold water. This set up a circulation motion in the water until all the water is evenly heated. The rising movement of the water carries energy with it. Fluids normally flow from a region of high temperature to the region of low temperature.

on passing the small ampere of electric current through the tube made of ar and hg of cfl generates uv rays which excites the fluorescent and thus emits the high radiation by consumption of just 5- 12 w in comparison to incandescent light which requires more power such as around 40 - 55 w to lighten.

moreover the life span of fluorescent or cfl is around 8000 h whereas the life span of incandescent is around 1200 h

hence, the building installed with incandescent lights bears more electricity bill.