Question

In an experiment similar to the Davisson-Germer experiment, an electron beam of the de Broglie wavelength 1.5 Å is allowed to fall normally on a crystal with interatomic spacing 3Å. Then at what angle from the incident direction, the diffraction peak will be observed?

• A. 15º
• B. 30º
• C. 45º
• D. 60º

Answer 1

Answer: (B)

30º

Answer 2

D sin q = nl

sin q =$\frac{n\lambda}{D}$= $\frac{1 \times 1.5}{3}$=$\frac{1}{2}$

q = 30º