Assume that the region to the right of a certain vertical plane contains a vertical magnetic field of magnitude $1.00 \mathrm{mT}$ and that the field is zero in the region to the left of the plane. An electron, originally traveling perpendicular to the boundary plane, passes into the region of the field. (a) Determine the time interval required for the electron to leave the "field-filled" region, noting that its path is a semicircle. (b) Find the kinetic energy of the electron assuming that the maximum depth of penetration into the field is $2.00 \mathrm{cm}$.