Compton effect and kinetic energy

[cassimoe]

Homework Statement

What is the maximum possible kinetic energy (keV) of a Compton electron and the corresponding minimum energy of a scattered photon resulting from scattering of

a) 100 keV photon
b) 1 MeV photon

Homework Equations

Δλ = 0.24(1-cosθ)

The Attempt at a Solution

Δλ = 0.24(1-(-1))
= 0.48A

I do not know how to figure the energy of the scattered photon

 

[cassimoe]

Compton Scatter

Homework Statement

what fraction of the energy of a 1 MeV photon is lost if it Compton scatters through an angle of 90 degrees

Homework Equations

Δλv= 0.24(1-cosθ)

The Attempt at a Solution

Δλv= 0.24(1-cosθ)
= 0.24(1-cos90)
= 0.24(1-0)
Δλ = 0.24A

I am confused from here

 

[jtbell]

OK, you've got the change in wavelength of the photon. What's the initial wavelength? (How do you find the wavelength of a photon given the energy?)

Then, what's the final wavelength?

 

[jtbell]

Threads merged. These two problems are actually rather similar, and you should be able to use basically the same technique to solve both of them. My hint applies to both of them.