Who was the first to verify that electrons are wave-like in nature?

Which phenomenon best supports the theory that matter has a wave nature?

In the Davisson-Germer experiment,for which value of accelerating voltage was the intensity of the electron beam found to be maximum (in $V$)?

Which of the following statements is incorrect regarding the Davisson-Germer experiment?

The 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 figure).

In the Davisson-Germer experiment,which is the correct curve between the intensity $(I)$ of scattered electrons and the scattering angle $(\phi)$?