Which statement is always true A all lithium atoms contain the same numbers of protons B All lithium atoms contain the same number of neutrons C All lithium atoms have the same mass D the sum of protons plus neutrons is the Sam in all lithium atoms

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.