Diffraction
is one of the property of waves, it is the ability of waves to bend around
geometric structures, It involves breaking up of waves and reconstruction of
waves through interference. diffraction occur when a waves passes through small
openings, around obstacles or relatively sharp edges.
Diffraction
of waves is of two types;
the fraunhofer
when the distance between the wave source and screen is far, the rays appear to
be parallel, this can be achieved
experimentally either by placing the
observing screen far from the opening or by using a convergence lens to focus the parallel rays on the screen .
a bright fringes
is observed along the axis at θ, the diffraction angle equal to 0. with alternating bright and dark fringes on
either sides of the central bright fringe.
in the other
hand, a Fresnel diffraction pattern is observed when the source and the diffracting
screen are place at a near distance, the waves appear to be non-parallel .the
wavefront in the diffraction is either spherical or cylindrical and convex lens
may be used.
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