➤ Example 1 The region between x=0 and x=L is filled with uniform steady magnetic field −B0k. A particle of mass m, positive charge q and velocity v0i travels along x-axis and enters the region of the magnetic field.
Neglect the gravity throughout the question.
(a) Find the value of L if the particle emerges from the region of magnetic field with its final velocity at an angle 30∘ to its initial velocity.
(b) Find the final velocity of the particle and the time spent by it in the magnetic field, if the magnetic field now extends upto 2.1L.