Question

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

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

Answer 1

Answer: (C)

Crystal structure is explored through the diffraction of waves having a wavelength comparable with the interatomic spacing $({10}^{-10}m)$ 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 camparable to interatomic spacing.