Conduction refers to heat transfer through which medium?

• A. Solid contact with another object
• B. Moving fluids or air
• C. Radiation from the sun
• D. Evaporation from skin

Answer: (A)

When heat is transferred by conduction, energy moves through direct contact between objects, typically via a solid in contact. The particles in the hotter solid collide with and transfer energy to the cooler solid, passing heat along through the material without any bulk movement of the substance. This is the classic scenario of conduction.

Convection involves moving fluids or air carrying heat as they flow, which is a different mechanism. Radiation transfers energy through empty space via electromagnetic waves, not by direct contact. Evaporation from a surface causes cooling through a phase change, not by conduction.

So the best description is solid contact with another object, which captures the essence of conduction’s mechanism.