Mumbai university > FE > SEM 1 > Applied Physics 1

Marks: 3M

Year: May 2014

X-Rays:-

• X-rays are electromagnetic waves having wavelength in the range of 0.01 to 10 nm, and frequencies in the range 3 × 10^{16} Hz to 3 × 10^{19} Hz.

• Energies in the range 100 eV to 100 KeV

• X-ray wavelengths are shorter than those of UV rays and longer than those of gamma-rays.

Why the X-rays are preferred to study crystalline solid: -

• Crystal structure is analyzed by using the diffraction pattern found after an electromagnetic wave is incident upon it.

• In order to get a regular diffraction pattern, the incident wave should have a wavelength comparable to the dimension of the object being observed.

• The dimensions of atom are of the order 10-10 m, which is comparable to the wavelength of X-ray.

• Hence, X-rays and not γ-rays are used to analyze crystals.