Final answer:
X-ray diffraction is the process where monochromatic X-rays scatter off a crystal and interfere at specific angles, leading to strong reflection known as Bragg's peaks.
Step-by-step explanation:
X-ray diffraction is a phenomenon where a beam of monochromatic X-rays is directed onto a crystal, causing the rays to scatter in all directions. When these scattered waves encounter one another while traveling in the same direction, they undergo interference, which can amplify or diminish the total wave intensity. This process is highly dependent on the angle of incidence — the specific angles where the scattered rays constructively interfere lead to pronounced intensity maxima, known as Bragg's peaks. This is the underlying principle of Bragg's law which relates the wavelength of the incident X-rays, the crystal lattice spacing, and the position of the interference maximum.