Understanding Heat Transfer Modes

Heat transfer occurs through three primary mechanisms:

• Conduction: Heat transfer via direct molecular contact, significant in solids.
• Convection: Heat transfer through the movement of fluids (liquids or gases).
• Radiation: Heat transfer via electromagnetic waves, requiring no medium.

The question asks where all three modes are significantly involved.

Analyzing Heat Transfer in Options

Boiler Furnaces and Heat Transfer

Boiler furnaces involve extremely high temperatures. This leads to:

• Radiation: Intense heat radiated from the combustion process and hot gases.
• Convection: Hot flue gases move, transferring heat to the boiler surfaces.
• Conduction: Heat is conducted through the boiler tubes to the water/steam inside.

Therefore, boiler furnaces utilize all three modes of heat transfer prominently.

Other Options Analysis

• Melting of ice: Primarily relies on conduction from the surroundings and potentially convection in air/water. Radiation might play a minor role.
• Condensation of steam: Heat transfer is mainly through convection (steam movement) and conduction (through walls to coolant). Radiation is minimal.

Conclusion on Heat Transfer

Based on the analysis, boiler furnaces are the most fitting example where heat is transferred by conduction, convection, and radiation simultaneously and significantly.