q (✗) (X BX B (X) L (X) WALL A magnetic field B= 1.3×103 T pointing directly into the screen is used to protect a wall from damage due to incident particles of mass m = 3×10-27 kg, positive charge q = 1.6×10-19 C, and velocity v = 2×104 m/s as shown. The width of the region within which the magnetic field exists is L. The thickness L of the region with the magnetic field must be larger than some thickness in order that the charged particles do not strike the wall. What is the thickness? L =

Fig: 1