Explain why the particle’s path in the magnetic field is an arc of a circle.
The radius of the arc in (a) is $r$. Show that the particle’s ratio $\frac{q}{m}$ is given by $\frac{q}{m} = \frac{v}{Br}$.
The particle’s initial speed $v$ is $2.0 \times 10^7\,\text{m s}^{-1}$. The magnetic flux density $B$ is $2.5 \times 10^{-3}\,\text{T}$. The radius $r$ of the arc in the magnetic field is $4.5\,\text{cm}$. Use these data to calculate the ratio $\frac{q}{m}$.
The route taken by the negatively-charged particle before it enters the magnetic field is shown in Fig. 6.1. The direction of the magnetic field is into the plane of the paper. On Fig. 6.1, sketch the particle’s path while it is in the magnetic field and after it leaves the field.
On Fig. 6.1, sketch the particle’s path in the magnetic field and after it emerges from the field.