Picking up a hot coal is an example of what type of heat transfer? conduction convection radiation transmission

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?

Ineed ! i have no clue how to do this problem.

In a copper wire, a temperature increase is the result of which of the following