Question

Explain the analogy between the flow of charge (or current) in a conductor under a potential difference with the free fall of a body under gravity. 

Answer 1

If a body is free to fall, on releasing it from a height, it falls downwards towards the earth's surface. For, this one end has to be at higher level and other at lower level, so that gravity could effect on this difference and body could freely fall. Same way to make flow of the charge through a conductor, the gravity of course has no role of play; there should be difference of electric potential. This difference gives the flow of charge in a conductor.