The lattice constant of a crystal is 2 Å. Then find the longest wavelength of X-ray that can be analysed with it.

Explanation

To find the longest wavelength of X-ray that can be analyzed with a crystal lattice constant of 2 Å, we will use Bragg's law, which is given by the equation:

\[ 2d \sin \theta = n \lambda \]

Where:
- \( d \) is the lattice constant,
- \( \theta \) is the angle of incidence of the X-ray,
- \( n \) is the order of reflection (an integer),
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