# Bragg Angles + Thermal Expansion

1. Sep 13, 2011

### exzacklyright

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

A crystal is heated from 0 to 100 degrees celcius, its lattice parameter 'a' increases by 0.17% due to thermal expansion. if we observe an x-ray reflection at a bragg angle theta= 19.3 degrees at 0 degrees celcius, by how much will theta change when the sample is heated to 100 degrees C. (don't need to know wavelength or d to solve)

2. Relevant equations

2dsin(theta) = n$\lambda$

3. The attempt at a solution

Tried using 1 for d. and just seeing how much it'd change but it didn't come out right.

2. Sep 13, 2011

### Spinnor

Should it be d_1*sin(theta_1) = d_2*sin(theta_2) ?

3. Sep 13, 2011

### exzacklyright

well all we're given is density 1 and theta 1. we don't even know density2 or theta2