Explain how a uniform electric field together with a uniform magnetic field can be used to select the velocity of a charged particle. A diagram may be included if you wish.
The ions, all belonging to the same isotope, move through a vacuum at a speed of $9.6 \times 10^4\,\text{m s}^{-1}$. They enter a uniform magnetic field of flux density $640\,\text{mT}$ at right angles. Before arriving at a detector, the ions travel along semicircular paths A and B, as shown in Fig. 6.1. The diameters of these paths are given in Fig. 6.2. Each ion in path B has charge $+1.6 \times 10^{-19}\,\text{C}$.
Find the mass, in $\text{u}$, of the ions on path B.
Suggest and give a quantitative explanation for why the radii of ion paths A and B are different.
Calculate the mass, in $\text{u}$, of the ions in path B.
Suggest and give a quantitative explanation for why the radii of ion paths A and B are different.