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Q.
In Davisson-Germer experiment, the wavelength associated with nickel crystal is
Dual Nature of Radiation and Matter
Solution:
For the nickel crystal, the interatomic separation is
$d=0.91 \,\mathring{A}$
According to Bragg's law, for first order diffraction maxima $(n=1)$, we have
$2 d \sin \theta =1 \times \lambda$
$\therefore \lambda =2 \times 0.91 \times \sin 65^{\circ}=1.65 \,\mathring{A}$