ia
bears the a constant ratio to the sin of ar.
This ratio is known as the refraction index. In another word, when a light passes
obliqely from one medium to another, it changes direction. This is the phenomenon
called refraction. The Refraction of Light
Light can travel through many materials, for instance, light can travel through glass which is transparent to light. When light passes from a medium such as air into another medium such as glass, there is a change in the direction of travel. The change of direction is also responsible for rainbows and the sparkle of diamonds. This is the basis for the field of fiber optics, which has revolutionized telecommunications and medical technology. The lenses used to correct vision problems and to construct microscopes and telescopes depend on the changes in direction that occur when light enters and leaves the lenses.
Fiber-optic technology
Light is passed through a plastic or glass fiber in order it can be directed to a specific location. Advantages include:
Science of geometric optics:
The law of Reflection: When a ray of light is reflected from a plane surface, the angle of incidence is equal to the angle of reflection.
The law of Refraction: When a light ray pass from one medium to another, the angle of refraction (ar) is not equal to the angle of incidence (ai).
Snell discovered that the sin ia
bears the a constant ratio to the sin of ar.
This ratio is known as the refraction index. In another word, when a light passes
obliqely from one medium to another, it changes direction. This is the phenomenon
called refraction.
In refractive system:
n1 sineia
= n2 sine ar
Where n is the index of refraction or refractive index. It is
n1 / n2 = sinear
/ sineai
defined as the ratio of the speed of light wave in a vaccuum to the speed of light wave in a medium.
The index (n) is:
n = C/Vm = 3*108 m/s / (speed of light of the medium)
Total Internal Reflection occurs when a light ray passes from a dense to a less dense medium both refraction and total internal reflection can occur.
