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Bragg's Law

X-rays reflected from parallel crystal planes interfere constructively when the path difference is a whole number of wavelengths.

Formula

nλ=2dsin⁡θn\lambda = 2d \sin\theta

Variables

nDiffraction order (integer)
\lambdaX-ray wavelength
dSpacing between crystal planes
\thetaGlancing angle

Example

Measuring diffraction angles reveals the atomic spacing inside a crystal.

Did You Know?

Bragg's law let Watson and Crick's colleagues capture the X-ray image that revealed DNA's double helix.

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