Question
(2) Assume 0.140 nm x-rays are diffracted on an interplanarspacing of NaCl, which is 0.281 nm.
a) What is the predicted angle in the first-order?
b) What is the predicted angle in the second-order?
c) What is the maximum order for reflection? Why?
Hi, I need help with the following question. Could you pleaseshow your work so that I may better understand how the solution wasachieved? Thanks! Upper plane d Lower plane Usethe figure as a reference for problems (1) and (2) (1)Potassium iodide has a crystalline structure with atomic planesseparated by 0.353 nm. A monochromatic x-ray shows a first-orderdiffraction maximum when the grazing angle is 7.60 degree. a) Calculate the x-ray wavelength b) Assume now that the x-ray is observed at an incident angle of31.9 degree. Will constructive interference occur? (Defend yourargument calculatively) (2) Assume 0.140 nm x-rays are diffracted on an interplanarspacing of NaCl, which is 0.281 nm. a) What is the predicted angle in the first-order? b) What is the predicted angle in the second-order? c) What is the maximum order for reflection? Why?
Explanation / Answer
(1). Separation of the atomic planes d = 0.353 nm = 0.353 *10 ^ -9 m
Grazing angle of first order maximum = 7.6degrees
We know from Bragg’s law 2 d sin = n
Where n = order
= wavelength = ?
From above equation wavelength = 2dsin / n
Where n = 1