Quiz

An electron with a speed of 100 m/s enters a capacitor through a hole in the negative plate.
The electric field strength in the capacitor = 3.8*10^(-6) N/C
The distance between the plates is 1 mm
The electron has a mass of approximately 9*10^(-31) kg and a charge of 1.6*10^(-19) C.
How deep into the capacitor can the electron fly?

The electron will experience a force equal to the electric field strength multiplied by its charge. This force will slow it down. To find the deceleration, this force must be divided by its mass. Furthermore, the distance it travels before stopping will be equal to the square of its initial velocity divided by twice the deceleration. However, it certainly cannot travel further than the distance between the plates. I will now calculate the values and try to create a diagram.

Added 2 minutes ago
The field strength is directed from the negative plate to the positive plate, and since the electron's charge is negative, the field will slow it down.

Added 25 minutes ago
The force that will slow down the electron: F = 3.8*10^-6*1.6*10^-19 = 6.08*10^-25 N
The deceleration will be: a = F/m = 6.08*10^-25/9*10^-31 = (6.08/9)*10⁶ m/s²
And the distance will be: s = v²/(2a) = 100²/(2*(6.08/9)*10⁶) = 10⁴/(10⁶*2*6.08/9) = 9/(100*2*6.08) = 9/1216 = 0.0074013157895 m. In short, it will reach the opposite plate :)