Areaction in which small nuclei combine to form a heavier nucleus is

The answer to your question is: Nuclear fussion

Explanation:

In Chemistry there are 2 nuclear processes:

Nuclear fission: is the process in which the nucleus of a radiactive element splits into two smaller nucleus, or two elements woth lower atomic number.

Nuclear fussion, is a reaction is which to small nucleus combine to form a heavier element.

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.