Question

A positively charged particle moving with velocity $v$ enters a region of space having a uniform magnetic field $B$. The particle will experience the large deflecting force, when the angle between $v$ and $B$ is:

• A. $ 0^{\circ} $
• B. $ 45^{\circ} $
• C. $ 90^{\circ} $
• D. $ 180^{\circ} $

Answer 1

Answer: (C)

Maximum force is experienced when angle between $v$ and $B$ is $ 90^{\circ}. $
Force experienced by a particle of change $q$,
travelling with velocity $ v $
in magnetic field $B$ is given by
$ F=qvB\,\sin \theta $
where $ \theta $ is angle between $ v $ and $B$
$ \therefore F_{m}=qvB\sin 90^{\circ }=qvB $