Calculate the wavelength of X-rays which produces a diffraction angle $2\theta$ equal to $16.80^{\large\circ}$ for a crystal.Assume first order diffraction with inter particle distance in crystal of 0.2 nm

Question

$\begin{array}{1 1}5.84\times 10^{-11}m\\4.84\times 10^{-12}m\\3.84\times 10^{-11}m\\6.84\times 10^{-11}m\end{array} $