Question

why kerosene stores and bunsen burners have small holes in them

Answer 1

Bunsen burner flames depend on air flow in the throat holes (on the burner side, not the needle valve for gas flow): 1. air hole closed (safety flame used for lighting or default), 2. air hole slightly open, 3. air hole half-open, 4.

Answer 2

kerosene stores and bunseen burners have small holes in them because oxygen is the supporter of combustion and if oxygen is not sufficient then any product will not burn