Question

X-rays are used in determining the molecular structure of crystalline, because

• A. Its energy is high
• B. can penetrate the material
• C. its wavelength is comparable to interatomic distance
• D. its frequency is low

Answer 1

Answer: (C)

its wavelength is comparable to interatomic distance

Crystal structure is explored through the diffraction of waves having a wavelength comparable with the interatomic spacing $\left({10}^{-10}m\right)$ in crystals. Radiation of longer wavelength cannot reslove the details of structure, while radiation of much shorter wavelength Is diffracted through inconveniently small angles. Usually diffraction of X-ray is employed in the study of crystal structure as X-ray have wavelength comparable to interatomic spacing.