Question

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

Answer 1

When a charge passes through a magnetic field, it experiences a force called Lorentz Force

$=qVB\sin \theta$

For force to be minimum,

$\theta =0°\text{or}180°$ thus

$F=0$ and it is along $\overrightarrow{B}$