Bragg's law
Bragg's law is the result of experiments into the
diffraction of
x-rays off
crystal surfaces at certain angles, derived by the English physicists Sir W.H. Bragg and his son Sir W.L. Bragg in 1913. Although simple, Bragg's law confirmed the existence of real particles at the atomic scale, as well as providing a powerful new tool for studying crystals in the form of
x-ray diffraction. The Braggs were awarded the
Nobel Prize in
physics in 1915 for their work in determining crystal structures beginning with NaCl, ZnS, and diamond.
Bragg's law is expressed by the equation:
where
- n is an integer,
- λ is the wavelength of x-rays, and moving electrons, protons and neutrons,
- d is the spacing between the planes in the atomic lattice, and
- θ is the angle between incident and diffracted rays
Note that moving particles, including electrons, protons and neutrons have an associated wavelength, as determined by
Louis de Broglie.
See also: