Which mode of heat transfer is carried by infrared radiation?

• A. Radiation
• B. Conduction
• C. Convection
• D. Heat

Answer: (A)

Infrared radiation is heat transfer via electromagnetic waves. Objects above absolute zero emit infrared radiation, and this energy can travel through space or through transparent materials, warming surfaces without needing to touch them. That’s why you feel warmth from a distant heater or the sun even though there’s empty space between.

This makes infrared radiation the mode of heat transfer called radiation—the energy moves through the air, vacuum, or other media as waves rather than by direct contact or by moving a fluid. Conduction, by contrast, requires molecular interaction through a solid, liquid, or gas, and convection involves the bulk movement of fluids carrying heat. “Heat” isn’t a transfer mechanism by itself, but the energy being transferred.