Question

In Davisson-Germer experiment, the wavelength of matter waves was found to be 0.165 nm. true=1, false = 0

Answer 1

Spacing of crystalline planes of nickel $d=0.091nm$

In Davisson-Germer experiment, maximum intensity of diffracted electron beam was found at different angles by varying the applied voltage to the electron gun from $44V$ to $68V$. The highest intensity was observed at an angle $\varphi ={50}^o$ with a voltage of $54V$, giving the electron a kinetic energy of $54eV$.

Using Bragg's law, $n\lambda =2d\sin (90-\frac{\varphi }{2})$

For $n=1$, we get $\lambda =2\left(0.091\right)\sin (90-\frac{50}{2})$

Or $\lambda =2\left(0.091\right)\sin \left({65}^o\right)$

Or $\lambda =2\left(0.091\right)\times 0.9$

$⟹$ $\lambda =0.165nm$