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

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

In the Davisson-Germer experiment,an electron beam of energy $75 \ eV$ falls normally on the surface of a crystal. If the maximum intensity is obtained at an angle of $45^o$ to the direction of the incident beam,then the inter-atomic distance in the lattice plane of the crystal will be .............. $\mathring{A}$

$A$ sodium atom is in one of the states labeled 'Lowest excited levels'. It remains in that state for an average time of $10^{-8} \, s$,before it makes a transition back to a ground state. What is the uncertainty in energy of that excited state?

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

Using the Heisenberg uncertainty principle,arrange the following particles in the order of increasing lowest energy possible.
$(I)$ An electron in $H_{2}$ molecule
$(II)$ $A$ hydrogen atom in a $H_{2}$ molecule
$(III)$ $A$ proton in the carbon nucleus
$(IV)$ $A$ $H_{2}$ molecule within a nanotube