Kinetic energy from plate A to plate B

[hanna.eunice]

Homework Statement

An electron acquires 3.45x10^(-16) J of kinetic energy when it is accelerated by an electric field in a computer monitor from plate A to plate B. What is the potential difference between the plates, and which plate is at the higher potential?

Homework Equations

KE=1/2mv^2

The Attempt at a Solution

The given answer is 2.16x10^3V...How and why?
Plate B has the higher potential.

 

[voko]

What is the potential energy of the electron at plate A?

 

[hanna.eunice]

Nothing is given other than the acquired electron energy of 3.45x10^(-16). Sorry!

 

[misterc]

Would the electron be attracted to a positive plate or a negative plate? Which plate (positive or negative) would have a higher potential?

Conservation of Energy: All the electric potential will be converted to kinetic.

 

[voko]

Nothing is given other than the acquired electron energy of 3.45x10^(-16). Sorry!

That is correct, but the electron still has some potential energy. How is it related to the difference of the plates' potentials?