Paragraph: Wave property of electrons implies that they will show diffraction effects. Davisson and Germer demonstrated this by diffracting electrons from crystals. The law governing the diffraction from a crystal is obtained by requiring that electron waves reflected from the planes of atoms in a crystal interfere constructively (see in figure).
Question: If a strong diffraction peak is observed when electrons are incident at an angle '$$i$$' from the normal to the crystal planes with distance '$$d$$' between them (see figure), de Broglie wavelength $$\lambda_{dB}$$ of electrons can be calculated by the relationship ($$n$$ is an integer)