i) Reflection of Waves:
“Bouncing
back of waves into same medium by striking other medium surface is called
reflection”
When a vertical straight surface is placed in the path
of the incoming waves the incident waves are reflected from the surface at the
same angle. It can be seen that the reflected waves obey the law of reflection.
For Example, the angle of the incident wave along the normal will be equal to
the angle of the reflected wave.
ii) Refraction of Waves:
“When
waves enter from one medium to another medium then as result the waves change
direction this is called Refraction of waves”.
When a flat piece of a block is immersed in the ripple
tank, water depth becomes shallow. You will find that the wavelength of the
plane waves shortens and changes direction, as they move from the boundary
between two media, deep to shallow water. However, the frequency of water waves
stays the same in both waves because it is the same as the frequency of the
vibrator. This result shows that the speed of a wave in water depends on water
depth. Waves travel faster in deep water than shallow water.
iii) Diffraction of Waves:
“The
bending of waves around an obstacle or spreading of waves near an obstacle is
called diffraction of waves.”
When an obstruction or a straight surface with a gap in
the ripple tank is placed in the path of the incoming water waves, they strike
it, the waves will bend around the sides of an obstruction or spread out as
they pass through a gap. This phenomenon is called diffraction. Diffraction is
only significant if the size of the gap is about the same as the wavelength of
the incident wave, narrow the gap whose width is equal to the wavelength of the
incoming ripples, the ripples that pass through the gap are almost circular and
seem to originate from a point source situated in the gap. Wider gaps produce
less diffraction.
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