In which of the following, heat loss is primarily not due to convection?

Heat transfer occurs via conduction, convection, and radiation [4]. Convection is the primary mode of heat transfer in liquids and gases, involving the actual movement of particles [4]. Boiling water is a classic example where buoyancy-driven fluid circulation (convection) heats the entire volume [3]. Land and sea breezes are also driven by convection currents caused by temperature differentials between land and water [1]. Similarly, the circulation of air around a blast furnace involves the movement of air (a gas), which is a convective process [4]. In contrast, the heating of a glass bulb's surface by a filament occurs primarily through radiation [4]. Since the interior of an incandescent bulb is often a vacuum or contains inert gas, heat travels from the hot filament to the glass surface via electromagnetic waves (radiation) rather than the bulk movement of fluid particles [4].

Sources

1. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 7: Heat Transfer in Nature > In a Nutshell > p. 102
2. [4] Science-Class VII . NCERT(Revised ed 2025) > Chapter 7: Heat Transfer in Nature > Let Us Enhance Our Learning > p. 103
3. [3] Science-Class VII . NCERT(Revised ed 2025) > Chapter 7: Heat Transfer in Nature > In a Nutshell > p. 101