Question

Under what condition is the force acting on a charge moving through a uniform magnetic field minimum?

Answer 1

lorentz force given by q(V X B) is the force acting ona charge due to a magnetic field by varying these parameters one can achieve
but remember that the force due to the magnetic field will be perpendicular to the direction of initial velocity of the particle and make it move in a curved path(not necessarily in a circle)

Answer 2

what i drew above is a special case of circular motion where
there shud be an initial velocitry perpendicular to the force acting(centripetal force like that)