91Ó°ÊÓ

The electron or proton's kinetic energy depends on the mass of the proton or electron and its velocity.An increase in the velocity of any of them will increase the kinetic energy.

The potential energy can be expressed as:

\(P.E = q\Delta V\)

Here, q is the charge of the subatomic particle and\(\Delta V\) is the change in the potential.

The potential energy of the particle decreases, and there is an increase in the kinetic energy.

The change in the potential for the electron is negative, and for the proton, it is positive. However, both have the same magnitude of change in potential.

Both have opposite signs since both are moving in the opposite directions in a uniform electric field.

The magnitudes of the charges on the proton and electron are the same, so the potential change also remains the same.

Since the increase in the final kinetic energy is equal to the decrease in the potential energy change, both have the same kinetic energies before they reach the oppositely charged plates.

Thus, both have the same kinetic energy.