A particle of mass m and charge q. moving with velocity v enters Region II normal to the boundary as shown in the Fig.21.144. Region II has a uniform magnetic field B perpendicular to the plane of the paper. The length of the Region II is l. Choose the correct choice (s).
(a) The particle enters Region III only if its velocity > qlB/m
(b) The particle enters Region III only if its velocity v < qlB/m
(c) Path length of the particle in Region II is maximum when velocity v= qlB/m
(d) Time spent in Region II is same for any velocity v as long as the particle returns to Region I
