Diffraction of light

• Diffraction is used in the design of optical instruments, for instance telescopes diffract light less than the eye, allowing more detail on celestial bodies to be seen.
• Wavefronts of water through a gap in a ripple tank will have breaks either side of them, as waves diffracted by adjacent sides of the gap will meet destructively, cancelling each other.
• Diffraction of light by a single slit can be observed by directing a parallel beam of light at the slit.
• The central fringe of light is twice as wide as the outer fringes (measured from minima to minima)
• The outer fringes are the same width
• The peak intensity of the fringes decreases as you move out from the centre.
• The greater the wavelength of the light, the wider the fringes.
• The narrow the slit, the wider the fringes.
• The width of the central fringe = (2 * wavelength * D)/a
• a = width of the single slit
• D = distance from slit to white screen
• W = width of central fringe