Diffraction of waves

When a waves meets a barrier or passes through a gap, the wave will bend around the edges or diffracted. The diffractrion effect is more obvoius when the size of the gap or barrier is about the same size of the wavelength.

When waves are diffracted, the direction of propagation and shape of the waves change while the wavelength, frequency and speed remains the same.
If the gap is bigger than the wavelength,
i ) the waves in the centre go through the gap unchanged
ii) the waves at the edges are diffracted.


If the barrier is bigger that the wavelength, a large shadow area is formed behind the barrier. the diffraction pattern of the waves is less obvious.

The pattern of light diffraction is not easily seen because it wavelength is small ( x 10 ^-7 m.