In which condition is the magnetic force acting on a given current - carrying rod placed in a magnetic field maximum and in which condition would the magnetic force not act on the rod ?
(Assume that the current through the rod and the strength of the magnetic field are not changed).

Explanation

(1) When the direction of the electric current passing through the rod is perpendicular to the direction of the magnetic field , maximum force is exerted on the rod.
(2) When the direction of the electric currnet is the same as that of the magnetic field or is opposite to that of the magnetic field , no force is exerted on the rod.