Question

The first question is the one I need help with, but both would be helpful

0.200 nm x-rays strike a crystal with a spacing of 0.400 nm between atoms. A film that reacts to x-rays is placed nearby. At what angles (measured off of the crystal surface) will x-rays reflecting off of the crystal produce a bright spot on nearby film? 1. A photon whose energy is 8.00 x 10-15Jis scattered off an electron at a 90° angle. what is the wavelength of the scattered wave? 2.

Answer 1

Given wave length T = 0.200 nm = 0.200 times 10^-9 m spacing, d = 0.400 nm = 0.400 times 10^-9 m angle, theta = 9 By Bragg's law we have n T = 2 d sin theta n - order of reflection T - wave length d - atomic spacing theta - angle of reflection Take n = 1 therefore n lambda = 2 d sin theta \r\n sin theta = n lambda/2 d = 1 times 0.200 times 10^- 9/ 2 times 0.400 times 10^-9 sin theta = 0.25 theta = sin^-1 (0.25) theta = 14.48 degree angle, theta = 14.48 degree Given energy, E = 8.00 times 10^-5 J we have E = h v E - energy h - plank's constant v - frequency \r\n E = h v E = 8 times 10^-15 J h = plank's constant = 6.6 times 10^-34 m^2 k g/s