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Light Diffraction

Diffraction is the phenomenon which explains a wave when it encounters an obstacle. The diffraction phenomenon is described as the apparent bending of waves around small obstacles and the spreading out of waves past small opening. Effects similar to this occur when light travels through a medium with a varying refractive index. Diffraction can occur with different types of waves. Physical objects have wave-like properties and therefore diffraction also occurs with matter. It can be studied according to the principles of quantum mechanics.

Diffraction can occur whenever propagating waves encounter changes. The effects are most pronounced for waves whose wavelengths are roughly similar to the dimensions of the diffracting objects. If obstructing objects proved multiple closely spaced opening, a complex pattern of varying intensity can result. This principle is due to the superposition or interference of different parts of a wave that travels to the observer through different paths.

Diffraction effects can be seen in everyday life. The common examples are those involving light. For example, the closely spaced tracks on a CD or DVD displays diffraction which is seen through the formation of a rainbow pattern. Diffraction in the atmosphere of small particles can cause a bright ring to be visible around a bright light source such as the sun or moon. 

Categories within Light Diffraction

Single slit

Postings: 9

A slit which is illuminated and diffracts the light into a series of circular waves.


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An aperture is an opening through which light travels.


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Grating splits and diffracts light into several beams which travel in different directions.

Light diffraction

Hi. Can someone please show me how to do the following problem? Thank you. "A diffraction grating has 2200 lines/cm. What is the angle between the first-order maxima for red light ( = 690 nm) and blue light ( = 410 nm)?"

White Light Diffraction

White light strikes a diffraction grating (540 lines/mm) at normal incidence. What is the longest wavelength that forms a third-order maximum?

What is the wavelength of the light shining on the grating?

A diffraction grating produces a first-order bright fringe that is 0.0934 m away from the central bright fringe on a flat screen. The separation between the slits of the grating is 4.27 10-6 m, and the distance between the grating and the screen is 0.625 m. What is the wavelength of the light shining on the grating?