The formation of dark and bright fringes is a result of the interference of light waves. When two or more light waves overlap, they can either reinforce each other (creating a bright fringe) or cancel each other out (creating a dark fringe).
The spacing of fringes, or the distance between bright and dark regions, is directly related to the wavelength of light. As the wavelength increases, the spacing also increases. This can be seen in the double-slit experiment, where the distance between fringes increases when a longer wavelength light source is used.
Yes, dark and bright fringes can be observed with any type of light as long as there is coherence between the light waves. Coherence refers to the waves maintaining a constant phase relationship, which is necessary for interference to occur.
The visibility of dark and bright fringes is affected by the intensity of the light source, the distance between the light source and the screen, and the distance between the two slits (in the double-slit experiment). A brighter light source, closer distance, and smaller slit spacing will result in more visible fringes.
The number of slits can affect the formation of dark and bright fringes. In the double-slit experiment, more slits will result in a greater number of fringes and a narrower spacing between them. However, for a large number of slits, the fringes will become too close together and eventually blur into a continuous pattern.