PROPERTIES of WAVES and LIGHT
Light moves tranversely - perpendicular to directon of movement.
Diffraction - When waves pass an object, it is diffracted - "bends" around the object. This can be seen when waves pass through blocks in water. The closer the blocks and the longer the wave length, the more it "bends" around the blocks. This can also be observed with light when you look at a blade or bearing and a border or dot appears. The dot on the bearing is known Arago-lightspot.
- Constructive : Two peaks in phase are added and larger peak is obtained.
- Destructive : Two peaks 180 degrees out of phase interfere and a smaller or no wave is obtained.
Reflection - When a wave hits a surface at a certain angle to the normal, it is reflected with the some angle relative to the normal. The angle between the incoming and reflected ray is twice the incoming or reflected ray's angle relative to the normal (line perpendicular to surface).
Refraction - When a wave or light moves from one medium to another and it changes the speed of the wave, it slightly changes direction. If passing from one medium in which it moves slowly into a medium in which it moves faster and the angle is larger than the critical angle, it will not leave the slow medium but will be internally reflected. This is known as Total internal Reflection. This concept is used in Binoculars and optic fibres.
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