Condensed Matter: Thermal Expansion coeff. using diffraction angles

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
Sign up Log in
1 reply · 2K views
themongrelcat
Messages
1
Reaction score
0

Homework Statement



At a temperature of 18°C a beam of diffracted monochromatic x-rays is observed at an angle of 150.8° to the incident beam after being diffracted by a crystal with cubic structure. At a temperature of 318°C the corresponding beam makes an angle of 141.6° with the incident beam. What is the mean coefficient of linear expansion of the crystal in the given temperature range?

Homework Equations



α=Δl/lΔT

possibly nλ=2dsinθ

The Attempt at a Solution



I already have ΔT and the equation for thermal expansion, but I have no idea how to get l and Δl. I know it must have something to do with the diffraction angles, maybe Bragg's Law? I've scoured the entire internet looking for an equation to relate the two, and I just can't find it. Even just an equation relating those would be helpful. Thank you!
 
Last edited by a moderator:
Physics news on Phys.org