Q1: When vaporisation takes place through a blanketting film of gas, the phenomenon is termed as __________ boiling.

ANS:D - film

When vaporization takes place through a blanketting film of gas, the phenomenon is termed as film boiling. In film boiling, a stable vapor film forms on the surface, which acts as a barrier between the liquid and the bulk gas. This film significantly reduces the heat transfer coefficient compared to other boiling regimes such as nucleate boiling. Film boiling typically occurs at relatively high heat fluxes and surface temperatures.