controls:

acceleration voltage Va
plate voltage Vp

$E=\frac {V_{\text p}}{\text d}=$ ${0}$ $\frac {\text V}{\text m}$

schematic diagram:

Schematic layout of the experiment
For the deflection of the electrons holds: the lower $V_\text{a}$, the bigger the deflection y(x).

Task:

Check if we have also: $y(x) \sim \frac{1}{V_\text{a}}$.
For checking the capacitor voltage $V_\text{p}$ is set to 3.2 kV. Complete the table at bottom of the page, by modifying the acceleration voltage and getting the missing values out of the experiment.
Real experiment about deflection of electrons in electric field of a plate capacitor grid for measurement
acceleration voltage ${V_\text{a}}$ 2 kV 2.5 kV 3 kV 3.5 kV
deflection by x = 5 cm cm cm cm cm
${V_\text{a}} \cdot\text{deflection}$