WILL GIVE BRAINLIEST

4. For A it's 0.6×10^9 years as that's when the mass percent reached 50%.

For B it's 4.5 × 10^9 years as that's when mass% reached 50%.

For C it's 13 × 10^9 years.

For D it's not visible on the graph. But it'll take at least another 14 × 10^9 years to reach half life.

5. A has the shortest half life since it took it less time to deplete to half of it's original mass percent.

6. A is unstable because it has the shortest half life and this means it'll take it very fast to decay.

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.