1. The problem statement, all variables and given/known data The boundary shown is that of a uniform magnetic field directed in the positive z direction. An electron enters the magnetic field with a velocity pointing along the x axis and exits 0.63 μs later at point A. What is the magnitude of the magnetic field? 2. Relevant equations F = qvb v = s/t r = mv/qb 3. The attempt at a solution I calculated v = 2m/0.63 x 10^-6s = 3174603m/s. But I am stuck after this next step. I know that q = 1.6 x 10^-19C. Is my approach to the question starting out right? I am confused and paralyzed, unable to proceed forward. Thanks if anyone could offer some hints.