Question

A proton is placed in an uniform electric field directed along the position x-axis. In which direction will it tend to move?

Answer 1

Proton as a positively charged particle will move along the field lines of electric field, in this case positive x axis. The direction of electric field lines originate from positive potential points to the negative potential points. Hence proton will move toward the negative potential points, that is, along the direction of the electric field direction.
As the electric field is directed from Positive (+ve) to negative ( -ve) and the positively charged proton gets attracted to the opposite charge (i.e., negative) and the proton moves in the direction of the electric field towards the –ve.