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685.


Problem 47.35 (RHK)


Monochromatic x rays are incident on a set of NaCl crystal whose interplanar spacing is 39.8 pm. When the beam is rotated from the normal, first-order Bragg reflection is observed. We have to find the wavelength of the x rays.


Solution:           Click For PDF Version

 It is given that the Bragg reflection occurs when the beam is incident at an angle of from the normal to the crystal planes. Therefore, the Bragg angle will be

For the first order Bragg reflection, we have the equation

where d is the interplanar spacing. For the NaCl crystal

Therefore,