Answer: The heat is transferred by the process of conduction of heat.
Explanation :
It is given that, Jimmy held the end of a metal bar over a fire while holding on to the opposite end.
After some time, the end he was holding began to get very hot.
The process of traveling heat from one end of the bar to the other end is called conduction. It is the process of transfer of heat by the interaction of particles and motion of electrons.