 
       
      
    A particle of mass m and charge q moves with a constant velocity v along the positive x direction. It enters a region containing a uniform magnetic field B directed along the negative z direction, extending from x = a to x = b. The minimum value of v required so that the particle can just enter the region x>b is
As we learnt in
Radius of charged particle -
-

For particle to enter x > b
Radius  (b - a)
   or       
Option 1)
incorrect
Option 2)
correct
Option 3)
incorrect
Option 4)
incorrect
