How large is the electron deflection when impinging on a screen placed in the distance s to the plate capacitor?

In technical applications for example an oszilloscope a screen is placed in distance \(s\) after the plate capacitor. This screen shows the impinge of electrons. So now the deflection \(\Delta y_{\rm{screen}}\) of the electrons at the screen must be calculated.Trajectory of the electrons after the deflection in a plate capacitor and impact on a screen


Electrons are leaving the plate capacitor (see picture) with an deflection of \(\Delta y_1=2.4\,\rm{cm}\). The electron velocity in x-direction is \(v_x=4.20\cdot 10^7\,\rm{\frac{m}{s}}\) ans in y-direction \(v_y=1.68\cdot 10^7\,\rm{\frac{m}{s}}\). The distance between the end of the capacitor and the screen is \(s=8\,\rm{cm}\).