3. The table below shows some characteristics of four substances at 1 atm pressure. Substance
Color
Melting Point (°C) Bolling Point (°C)
-7
59
Bromine
Red-brown
Chlorine
-101
-34
Ethanol
Green-yellow
Colorless
Silver-white
-117
78
Mercury
-39
357
Which of the following substances is a liquid at temperatures ranging from -50°C to 0°C?
A. bromine
B. chlorine
C. ethanol
D. mercury

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.