Question

what is meant by bulk phenomena

Answer 1

There are two types of phenomenon. One is surface phenomenon and the other being bulk phenomenon.
Surface phenomenon is the phenomenon where only surface of any substance or object is involved in the process. For e.g. evaporation, while bulk phenomenon refers to the phenomenon where whole of the substance or object is involved in the process and is affected in bulk completely. For e.g boiling.

Answer 2

Explanation:

Bulk phenomenon: The process which involves total molecules including interior molecules along with surface molecules is called as bulk phenomenon. Example: Boiling of any liquid. When compared with evaporation it involves only surface molecules, so evaporation is considered as surface phenomenon but not as bulk phenomenon.