10.2.1. Space is divided into two regions by a plane. In one region, a magnetic field of induction $B_{1}$ is created, in the other — of induction $B_{2}$, and the fields are homogeneous and parallel to each other. An electron starts from the interface plane perpendicular to it with velocity v towards the region with field induction $B_{1}$
For problem $10.2.1$ . Describe the further movement of the electron. Determine the average (drift) velocity of an electron moving along the magnetic field interface that is permeable to it.
Solution
$$v = \frac{\Delta R}{\Delta t}= \frac{2(R_{2}-R_{1})}{\frac{T_{1}+T_{2}}{2}}$$ , Radii of curvature for the circular paths in the two regions are : $R_{1} = \frac{mv}{eB_{1}} , R_{2} = \frac{mv}{eB_{2}}$ . Periods of revolution are $T_{1} = \frac{2\pi R_{1}}{v} ,T_{2} = \frac{2\pi R_{2}}{v}$ : $$v = \frac{2}{\pi}\frac{{B_{1}-B_{2}}}{{B_{1}+B_{2}}}$$ , the drift velocity in the field.
