1. A beam of 6Li and 7Li ions passes through a velocity selector and enters a magnetic spectrometer. If the diameter of the orbit of the 6Li ions is 15 cm, what is the diameter of that for 7Li ions?

2. A beam of positively charged particles passes undeflected from left to right through a velocity selector in which the electric field is up. The beam is then reversed so that it travels from right to left. Will the beam now be deflected in the velocity selector? If so, in which direction?