Which aspect of heat transfer is dependent on a material's thermal conductivity?

The aspect of heat transfer that is dependent on a material's thermal conductivity is conduction. Conduction is the process by which heat energy is directly transferred through a material, typically as a result of collisions between neighboring atoms or molecules. Thermal conductivity is a measure of how easily heat can flow through a material; materials with high thermal conductivity, like metals, allow heat to pass through them more easily than materials with low thermal conductivity, such as wood or rubber.

In conduction, the rate at which heat is transferred through a material is directly proportional to its thermal conductivity. The higher the thermal conductivity, the faster heat can be conducted through that material. This is because energetic particles in the hotter region of the material collide with neighboring cooler particles, transferring energy and thus raising the temperature of the cooler particles.

Conversely, convection involves the movement of fluids (liquids or gases) and does not rely on the thermal conductivity of the materials involved, but rather on fluid motion and temperature differences. Radiation involves the transfer of heat through electromagnetic waves and also does not depend on thermal conductivity, as it can occur in a vacuum without any material medium at all. Therefore, the unique dependence of conduction on thermal conductivity clearly identifies why it is the correct choice in this context.