X-ray Diffraction, Intensity vs. Wavelength Graph

[Mxbn0]

Homework Statement

[PLAIN]http://b.imagehost.org/0607/Question_7.png

Homework Equations

[PLAIN]http://d.imagehost.org/0813/Untitled_6.jpg

The Attempt at a Solution

I was able to get question b, which ends up being 73pm, but as for questions a and c, I was unable to come up with an explanation, and even when I sort of did, I couldn't explain it well. For question a, I can't figure out why the carbon is there, as well as the crystal and for question c, is it to do with the x-rays hitting either 1. the electron cloud or 2. the nucleus itself (compton collision) ?

 

[Rajini]

Hi,
please tell us how did you calculate 73 pm ?

 

[Mxbn0]

You find delta-lambda, equals to 2, where theta in this case is equal to 90, then you add it onto the initial value of 73pm given.

 

[Rajini]

Hi,
I have some doubts:
In figure i notice only theta angle, but no psi angle! [is your question taken from book or some other sources?]
for a) I guess, one can apply the famous law that relates incident angle and scattering plane's angle.
b) use the same law from (a)
c) it is a type of scattering (incident and scattered X-ray have same wavelength!)
PS: I have some doubts for (b), but a and c should be okay.
hope it helps.

 

[Mxbn0]

I pulled the formula from the formula sheet off the back of last years exam. I've done the exam now, so I'm not stressing about it, and nor was there a question about this too much on the exam I did, I was just wondering because finding a solid answer is hard.

And yes, I know how to use 2d*sin(theta)=n*lambda

b was correct, from last years answer sheet, but the answer for a and c was 'explanation required'

In the exam I just completed, there was a similar question and it hinted at K-alpha and K-beta energy differences. Is this correct? No need to be so cryptic, lol, just curious, not actually homework anymore.