# Finding the shortwavelength limit of the white spectrum

## Homework Statement

I am trying to find the short wavelength limit ( and consequently plankcs constant) of the white or bremstrahlung spectrum. The data came from the bragg scattering of x-rays produced from a copper anode scattered of a NaCl crystal. The graph is counts vs degrees. The spectrum is from 11-30º on a 2-theta scale. There were two trials for the white spectrum, one of 20 KeV x-rays and the other of 30 Kev x-rays. The shortwavelength limit is defined as the intersection of the x-axis.

One of the main equations is,

$$hf\; =\; h\left( \frac{c}{\lambda } \right)\; =\; \mbox{E}\; =\; 20\; KeV$$

## Homework Equations

The problem is that my data is in counts vs degrees, not counts vs wavelength. I need my x-axis to be in wavelength, not the recorded degrees. I am not sure how to convert it.

## The Attempt at a Solution

I am a bit clueless on this one. I tried using 2d*sin(theta) = n*lambda to convert the degree axis into a wavelength axis, I knew it would be wrong iand sure enough, I got a planck's constant of five magnitudes off.