Question

In the Bragg’s equation for diffraction of X - rays, n represents for
(A) the number of moles
(B) quantum number
(C) the order of reflection
(D) Avogadro’s number

Answer 1

Hint: The Bragg gave a mathematical equation to determine interatomic distance with the formula-
$n\lambda =2\text{dsinθ}$
Where $\lambda$ is the wavelength
$d$ is the interatomic distance
$n$ = 1, 2, 3, 4 etc.

Complete step by step solution:
Bragg studied the X-ray diffraction pattern of various solids. They gave a mathematical equation to determine interatomic distance. The inter-atomic distance is the distance between two atoms.
The formula is written as
$n\lambda =2\text{dsinθ}$
Where $\lambda$ is the wavelength
$d$ is the interatomic distance
$n$ = 1, 2, 3, 4 etc.
It represents the order of reflection from the solids.

Thus, the option (C) is the correct answer.

Additional information:
The Bragg’s equation occurs when the electromagnetic radiations have wavelengths comparable to atomic spacing in the crystal system.
Bragg's equation explains why the faces of crystals reflect X-ray beams at particular angles of incidence. Further, in the X-ray Fluorescence spectroscopy and wavelength dispersive spectroscopy, the crystals of known spacing can be used to analyse the crystals.
The interplanar spacing is even used to characterize and identify any crystal with the use of X-ray spectroscopy.

Note: Bragg’s equation has nothing to do with the number of moles. It is to study the structure of solids. Avogadro’s number is also not used here. The quantum numbers also have nothing to do with the structure of solid.