In Davisson-Germer experiment, the function of Ni-crystal is

Detailed Solution:

In the Davisson-Germer experiment, the function of the nickel (Ni) crystal is to act as a diffraction grating, which scatters the incident electron beam in a specific way.

The experiment involved firing a beam of electrons at a nickel crystal, which acted as a diffraction grating, scattering the electrons in a pattern that was detected by a detector screen. The pattern observed on the detector screen was an interference pattern, similar to the pattern observed in the famous double-slit experiment with light, indicating the wave-like behavior of electrons.

The Ni-crystal acted as a periodic lattice of atoms, which cause the electrons to scatter in a specific pattern due to the interference between the scattered waves. The resulting diffraction pattern provided important evidence for the wave-particle duality of electrons, confirming that electrons can exhibit both wave-like and particle-like behavior depending on how they are observed or measured.

Hence, the correct option is A