Please explain diffraction of light .

Diffractionrefers to various phenomena which occur when a wave encounters an obstacle or a slit. In classical physics, the diffraction phenomenon is described as theinterferenceof waves according theHuygens Fresnel principle. These characteristic behaviours are exhibited when a wave encounters an obstacle or a slit that is comparable in size to its wavelength. Similar effects occur when a light wave travels through a medium with a varyingrefractive index, or when asound wavetravels through a medium with varyingacoustic impedance. Diffraction occurs with all waves, including sound waves,water waves, andelectromagnetic wavessuch asvisible light,X-rays andradio waves.