Who made experimental verification of the wave nature of the electron?

The Davisson-Germer experiment is the direct evidence of

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

State Heisenberg's uncertainty principle.

The Davisson-Germer experiment that first demonstrated the wave nature of matter used electrons accelerated to $54 \ V$. Determine the wavelength of the electrons in the Davisson-Germer experiment in $\mathring{A}$.

In the Davisson-Germer experiment,an electron beam with a wavelength of $1.5 \ \mathring{A}$ is incident normally on a crystal with an atomic spacing of $3 \ \mathring{A}$. At what angle (in degrees) will the first maximum be formed?