Final answer:
The speed of the electron, when it reaches the bottom plate, can be determined using the equation vf = vi + at, where vf is the final velocity, vi is the initial velocity, a is the acceleration, and t is the time taken.
Step-by-step explanation:
Given a proton released from rest just above the lower plate with a certain speed and an electron released from rest just below the upper plate, we can determine the speed of the electron when it reaches the bottom plate. When the electron is released, it will experience an electric force due to the electric field between the plates. This force will accelerate the electron and increase its speed as it moves toward the bottom plate.
The electric force (Fe) experienced by an electron in an electric field is given by Fe = qeE, where qe is the charge of the electron and E is the electric field strength. The acceleration (a) of the electron is given by ae = Fe/me, where I is the mass of the electron.
Using the equation vf = vi + at, where vf is the final velocity, vi is the initial velocity (0 as the electron starts from rest), a is the acceleration, and t is the time taken, we can find the speed of the electron when it reaches the bottom plate.