Define the term electric field.
Fig. 5.1 depicts two parallel conducting plates in a vacuum. Their separation is $6.7\ \text{cm}$, and the p.d. across them is $430\ \text{V}$.
On Fig. 5.1, sketch four field lines to show the electric field between the plates.
Determine the electric field strength $E$ between the plates.
An electron is moving towards the region between the plates at a speed of $2.6 \times 10^{7}\ \text{m s}^{-1}$, as shown in Fig. 5.1. On Fig. 5.1, sketch the path of the electron as it passes through and beyond the plates.
A uniform magnetic field is now applied to the region containing the electric field in Fig. 5.1, so that the electron in (b)(iii) passes through the region undeviated.
Determine the direction of the uniform magnetic field.
Explain, with reference to the forces exerted by the two fields on the electron, why the electron’s path is undeviated.
Determine the flux density $B$ of the uniform magnetic field. Include a unit in your answer.