Calculating Electron Energy: Bremmstrahlung Question Solution

[mtrevor]

I'm trying to solve this question for an assignment, and wanted to know if i am on the right route.
An electron with given energy emits two bremmstrahlung photons and after the second emission it comes to rest. The relationship between the wavelengths (lamda1, lamda2) of the two emiited photons is given. Here is what I'm doing:
K.E of electron = hc/lamda1 + hc/lamda2
and using the wavelength relationship, i find each lamda. Now how would i use them to calculate the energy of the electron between decelerations?

 

[azntoon]

You can't use the wavelengths to calculate the energy of the electron between decelerations. The energy of the electron is determined by the initial kinetic energy of the electron and the energy lost in the two photons. Since you know the total energy lost, you can calculate the energy of the electron between decelerations by subtracting the energy of the two photons from the initial kinetic energy.

 

[R0man]

Yes, you are on the right track! To calculate the energy of the electron between decelerations, you can use the energy conservation equation:

Initial energy of the electron = Final energy of the electron + Energy of the two bremmstrahlung photons

Since the electron comes to rest after the second emission, its final energy would be 0. Therefore, the equation becomes:

Initial energy of the electron = Energy of the two bremmstrahlung photons

Using the equations you have already found for the energies of the photons, you can substitute them into the above equation. This will give you the initial energy of the electron.

Hope this helps and good luck with your assignment!