Express v2, the speed of the electron at point 2, in terms of δu, and the mass of the electron me.

(a) write an equation for the change of electric potential energy change of U of the electron in terms of the symbols given.

(b) find the numerical value of the change of the electric potential energy in electron volts (eV)

(c) express v2, the speed of the electron at point 2, in terms of change in U, and the mass of the electron me

(d) find the numerical value of v2 in m/s"

(a) Calling  the electron charge, the variation of the electric potential energy is:

(b) Using the value of e, and of V1 and V2, we can calculate the variation of electric potential energy of the electron going from point 1 to point 2:

(c) The electron lost -111 eV of electric potential energy moving from point 1 to point 2. This energy has converted into kinetic energy:

where v is the electron velocity in point 2 and me is the electron mass. So we can write v as

(d) and then, we can calculate the value of the electron velocity. First we have to convert  from eV to joule:

So, using the electron mass , we have:

this means that the temperature of both substances will be equal