Define magnetic flux density.
Electrons travel in a vacuum at speed $1.7 \times 10^7\,\text{m s}^{-1}$. The electrons enter a uniform magnetic field of flux density $4.8\,\text{mT}$. Fig. 6.1 shows the electrons’ path. The electrons’ path stays in the plane of the page.
State the direction of the magnetic field.
Show that the magnitude of the force exerted on each electron by the magnetic field is $1.3 \times 10^{-14}\,\text{N}$.
On Fig. 6.1, draw an arrow to show the direction of the centripetal acceleration of the electron as it enters the magnetic field at point X.
Use the information in (b)(ii) to calculate the distance $d$ between the path of the electrons entering the magnetic field and the path of the electrons leaving it.
The electrons in (b) are replaced by positrons moving at speed $3.4 \times 10^7\,\text{m s}^{-1}$ along the same initial path as the electrons. The positrons enter the magnetic field at point X on Fig. 6.1. On Fig. 6.1, draw a line to show the path followed by the positrons through the magnetic field.