Heat transfer through solid objects that are in contact with one another occurs by which mechanism?

Heat transfer through solid objects that are in contact with one another occurs by which mechanism?

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

Answer: (D)

When solid objects are in contact, heat moves mainly by conduction. In a solid, particles are tightly packed, so when one region is hotter, those particles have more energy and transfer some of it to neighboring particles through collisions and interactions. In metals, free electrons also carry energy rapidly from the hotter region to the cooler region, speeding up conduction. This transfer happens through direct contact and without bulk movement of the material. Convection would require a moving fluid to carry heat, which isn’t the case for solids in direct contact. Radiation transfers energy by electromagnetic waves and can occur across empty space, so it isn’t the mechanism for heat moving between solid bodies that are touching. Diffusion refers to the spread of substances due to concentration differences, not the primary mode of heat transfer between solid objects in contact. Therefore, conduction is the correct mechanism.

When solid objects are in contact, heat moves mainly by conduction. In a solid, particles are tightly packed, so when one region is hotter, those particles have more energy and transfer some of it to neighboring particles through collisions and interactions. In metals, free electrons also carry energy rapidly from the hotter region to the cooler region, speeding up conduction. This transfer happens through direct contact and without bulk movement of the material.

Convection would require a moving fluid to carry heat, which isn’t the case for solids in direct contact. Radiation transfers energy by electromagnetic waves and can occur across empty space, so it isn’t the mechanism for heat moving between solid bodies that are touching. Diffusion refers to the spread of substances due to concentration differences, not the primary mode of heat transfer between solid objects in contact. Therefore, conduction is the correct mechanism.