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## Homework Statement

X-rays of wavelength 0.09 nm are incident on a crystal. A reflected beam is observed at 36 degrees from the incident beam. What is the spacing of the planes in the crystal?

## Homework Equations

Bragg's law:

[itex]2 d \ sin \theta = m \lambda[/itex]

## The Attempt at a Solution

I thought this is a simple application of Bragg's law but I get

[itex]2 d \ sin \ 36 = 0.09 \times 10^{-9} \implies d=7.65 \times 10^{-11}[/itex]

But the answer should be 4.73 x 10

^{-11}m. What's wrong with my calculation?