Let Fr, FL, respectively, be the resistive force and the Lorentz force, v0 is the initial speed of the charged particle. Also, l0 = 20 cm and l1 = 12 cm, B is the magnitude of the initial magnetic field, and l2 is the distance from the entry point to the position which particle stops if the magnitude of the magnetic field is B2=B2.

Applying Newton’s 2nd law, we have:
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