Question

What is the difference between diffraction and scattering of light?

Answer 1

Diffraction is a phenomenon observed only in waves, but scattering is a phenomenon observed in both waves and particles.

• Diffraction is a property of propagation of waves, whereas scattering is a property of wave interactions.

• Diffraction can be taken as evidence for the wave nature of light. Some forms of scattering (Compton scattering) can be taken as evidence for the particle nature of light.

Diffraction is a phenomena observed in waves. Diffraction refers to various behaviors of waves when it meets an obstacle. The diffraction phenomenon is described as the apparent bending of waves around small obstacles and the spreading out of waves past small openings. This can be easily observed using a ripple tank or a similar setup. The waves generated on the water can be used to study the effects of diffraction when a small object or a small hole is present. The amount of diffraction depends on the size of the hole (slit) and the wavelength of the wave. For diffraction to be observed, the width of the slit and the wavelength of the wave must be of the same order and or nearly equal. If the wavelength is much larger or much smaller than the width of the slit, an observable amount of diffraction is not produced. Diffraction of light through a small slit can be considered as evidence for the wave nature of light. Some of the most famous experiments in diffraction are Young’s single slit experiment and Young’s double slit experiment. The diffraction grating is one of the most useful products based on the theory of diffraction. It is used to obtain high-resolution spectra.

What is Scattering?

Scattering is a process where waves are deviated due to certain anomalies in the space. Forms of radiation such as light, sound and even small particles can be scattered. The cause of scattering can be a particle, a density anomaly, or even a surface anomaly. Scattering can be considered as an interaction between two particles. This is very important in proving the wave particle duality of light. For this proof, the Compton Effect is taken. The reason for the sky being blue is also due to scattering. This is due to the phenomenon called the Rayleigh scattering. The Rayleigh scattering causes the blue light from the sun to be scattered more than other wavelengths. Due to this, the color of the sky is blue. Other forms of scattering are Mie scattering, Brillouin scattering, Raman scattering, and inelastic X-ray scattering.