# Kinetic energy from plate A to plate B

1. Feb 24, 2013

### hanna.eunice

1. The problem statement, all variables and given/known data
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?

2. Relevant equations
KE=1/2mv^2

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

2. Feb 24, 2013

### voko

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

3. Feb 24, 2013

### hanna.eunice

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

4. Feb 24, 2013

### 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.

5. Feb 25, 2013

### voko

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