Objective: Demonstrate the wave nature of light and determine the wavelength.
The diffraction of light by multiple slits or a grating can be described by considering how the individual components of the coherent wave radiation are superimposed as they emerge from the various slits, which can each be regarded as a single point of illumination so that the waves superimpose according to Huygens principle. The interference of the individual waves explains the pattern of bright and dark bands that is observed beyond the system of slits. If the the separation between the slits and the distance to the observation screen is known, the wavelength of the light can be calculated from the distance between any two bright bands.
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