1. The light rays emanating from the object at the center of the sphere pass radially out of the sphere. Radius is normal to the surface. So angle of incidence and refraction are both 0. So All the rays appear to diverge from the center C. A virtual image is formed at the center of the sphere.
Thus the electron makes a circle, as the force and the acceleration on it are always perpendicular to the magnetic field and the velocity. The force is the centripetal force. As the force is in the - Y direction, e makes a semi circle on the -Y axis.
m v²₀ / R = e v₀ B₀
R = m v₀² / (e v₀ B₀)
The electron touches the y axis at -2 R.