Physics - Modern Physics Question with Solution | TestHub

For scattering to occur, the wavelength of the waves must be of the same order of magnitude or smaller than the size of the object being observed. Hence, the largest possible wavelength we can use in the present problem is${\lambda }_{max}=2.5 \mathrm{Å}$. Hence, minimum energy is

$E_{min}=h{v}_{min}=\frac{hc}{{\lambda }_{max}}=\frac{12.40\times {10}^3 \mathrm{eV}.\mathrm{Å}}{2.5 \mathrm{Å}}=5 \mathrm{keV}$