Question

A charged particle with mass m, charge |q|=6.4 ×10−19C and speed v=3 ×106 m/s enters from the bottom of the figure and traces out the trajectory shown in the fields shown. The only electric field E=5 ×103 V/m is in the region where the trajectory of the charge is a straight line.

(a) When the particle is moving through the first (straight-line) segment of its trajectory, what is the magnitude of the magnetic field B in Tesla?

(b) The charge hits the left wall of the spectrometer at a vertical distance h=0.114 m above where it entered the upper region and a horizontal distance L=0.272 m to the left of where it entered the upper region (see sketch). What is the radius r of the trajectory in m?

(c) The mass of the particle can be determined using the radius r, the charge q, the speed v, and the magnetic field B0. Using a value of B0=0.6 T, evaluate the mass of the particle in kg. (Note that the magnitude of the field in the curved section, B0, is NOT the same as the magnitude in the straight section, B, found in part a).