X-rays explanations

1. May 6, 2012

Noirchat

I'd really like some explanations please, just looking at part (a) at the moment :)

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

Suppose three 1.02 MeV X-ray photons are Compton scattered by single collisions with nearly stationary electrons.
Photon 1 is scattered backwards, in the direction opposite to its original path.
Photon 2 is scattered at right angles to its original path.
Photon 3 is scattered in a direction 45° away from the forward direction.

(a) Calculate the change of wavelength for each case. Show your working.
(b) Suppose instead, the original photons energies were 0.51 MeV. What effect does this have on the values calculated above? Explain very briefly.

2. Relevant equations
None were given

3. The attempt at a solution

(a) I think i use Δλ=h/mc(1-cosθ)

Photon 1:

Photon 2:

6.626 X 10^-34/9.1094x10^-31 x 3x10^8 x (1-cos90

= 0

Photon 3:

6.626 X 10^-34/9.1094x10^-31 x 3x10^8 x (1-cos45)

= 8.666x10^-13

Last edited by a moderator: May 7, 2012
2. May 7, 2012

vela

Staff Emeritus
Re: X-rays

This would be a relevant equation.

Did you have a specific question? Your answers are not correct, by the way.

3. May 7, 2012

Noirchat

Great I'm on the right track then. Hmm I'm not sure why they're incorrect. Is it to do with the Compton constant?