The thermometers show the variation in temperatures of a rod at different points. What process of heat transfer causes this variation? conduction convection emission radiation

conduction

Explanation:

Heat conduction is the transfer of internal thermal energy by the collisions of microscopic particles and movement of electrons within a body. The microscopic particles in the heat conduction can be molecules, atoms, and electrons(Science direct).

From the statement above, heat is transferred via conduction when the particles in a body collide with each other. The heat energy gradually travels through the entire length of the material(initially found to exhibit variation in temperature with length) causing an increase in temperature starting at the part of the rod directly exposed to the heat source until the temperature becomes uniform throughout the rod.