Coefficient of linear expansion / Bragg peaks

[kiki1]

Homework Statement

Measurements of XRay scattering from a metal are made. The bragg peaks are θ = 53° and 48° for temperatures of 300K and 1272K.

What is the linear expansion coefficient?

Homework Equations

linear expansion coef is given by (1/L)(dL/dT)
Bragg equation (differential form) δd / d=δθ / tan θ.

The Attempt at a Solution

I don't know where to start with this question, any advice would be appreciated.

 

[M Quack]

what is the relationship between L and d? and between delta L and delta d?