# Homework Help: Bohr model equations

1. Dec 11, 2011

### Woopy

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

Write an expression relating the kinetic energy KE of the electron and the potential energy PE in the Bohr model of the hydrogen atom. (Use any variable or symbol stated above as necessary.)

b) Suppose a hydrogen atom absorbs a photon of energy E, resulting in the transfer of the electron to a higher-energy level. Express the resulting change in the potential energy of the system in terms of E.

(c) What is the change in the electron's kinetic energy during this process? (Use any variable or symbol stated above as necessary.)

2. Relevant equations

THATS THE QUESTION!

3. The attempt at a solution

KE = -PE
Ef - Ei
KEf - KEi

2. Dec 12, 2011

### Delphi51

I don't think KE = - PE. How did you arrive at this?
I used centripetal force = electric force for a circular orbit to get the velocity and kinetic energy. I integrated F*dr in from infinity (where PE = 0) to get the PE. I found a simple relationship between KE and PE, but not that one.