Thermal radiation is defined as what?

Thermal radiation is the radiation emitted by a body due to its temperature. This radiation is electromagnetic radiation that is generated by the thermal movement of the charged particles in matter.

This type of energy can be transferred in three different ways: 1) direction contact through collisions (also called conduction), 2) through a fluid making a current created by less dense fluids floating and more dense fluids sinking (also called convection), and 3) by waves traveling with or without a medium (also called radiation)  

This is: physically, heat is understood as the energy that is transferred from one system to another or from one body to another, a transfer linked to the movement of molecules, atoms and other particles.

wire in brush may conduct electricity from cell to drill and vice versa electrc shock possible