Question

Under what condition, the diffraction from the lattice will not occur :

• A. $\frac{n\lambda}{2d} > 1$
• B. $\frac{n\lambda}{2d} < 1$
• C. $\frac{n\lambda}{2d} = 1$
• D. $\frac{n\lambda}{d} > 3$

Hint:

Because $\sin\theta \le 1$, Bragg diffraction is impossible if $\lambda > 2d$. This is exactly why visible light ($\lambda \sim 500\text{ nm}$) cannot diffract through crystal lattices ($d \sim 0.1\text{ nm}$); you must use X-rays or electrons with much smaller wavelengths!

Answer 1

The Correct Option is A