Why does snell law work

It is this type of total internal reflection that gives rise to fiber optics. A very important application of Snell's Law is Fiber Optics. Fiber Optics are used for many applications, from telecommunications to data transmission in high speed servers. Because the fibers are not laid out in straight lines, the light must be guided down the length of the fiber. This is achieved with one of three types of fiber: step-index fiber, graded-index fiber multimode , or single-mode fiber.

These fiber types are shown in Figure 4. Figure 4: Schematics and comparison of Fiber Optic Cable types. In step-index fibers, there is a very large decrease in the index of refraction at the interface between the glass fiber and its cladding. This causes the light to move in a zigzag pattern down the length of the fiber, and because of this there is a considerable distortion in the light pulse. It is because of this distortion that step-index fibers are only used for applications that have shorter fiber lengths.

For graded-mode fibers, the index of refraction of the core decreases mas the radius of the fiber gets larger. This is achieved by introducing additives to the fiber glass, such as B 2 O 3 and GeO 2. By having the index of refraction change gradually, the light is gradually bent back towards the center of the fiber. Therefore, the distortion of the light is much smaller than it is for the step-index fiber.

This means that a longer fiber can be used if the fiber has graded-index core. Graded-index core fibers are generally used for data transfer, such as in local area networks.

The final type of fiber is the single-mode fiber. Single-mode fibers are generally used for long distance networks where there is very little need for a curve in the fiber. In single-mode fibers, the light travels straight down the axis of the fiber and does not experience refraction. This is shown in Figure 4. Speed of Light and Index of Refraction Refraction occurs because the speed of the light changes when it passes into a new medium.

Theory: Light as a Wave Snell's Law arises from the wave nature of light. Questions Calculation of Transmittance Angle Using values given in Table 1, calculate the angle of transmittance if the incident angle of the light is 26 o.

The light is moving from air into glass. Is Snell's Law only for solid materials? Which direction will light bend towards or away from the normal if the index of refraction for the second material in the interface is higher than the first? The angles in this equation are referenced to a surface normal, as is illustrated below. In the following figure, a ray is incident on an interface between two dissimilar media. A plane that includes the incident ray and a line drawn normal to the surface is called the plane of incidence.

This plane also contains the reflected and refracted rays. A refracted ray is transmitted into the second medium and travels in a different direction than the incident ray. The angle that the incident, reflected, and refracted rays make with the surface normal are called the angles of incidence, qi , reflection, qr, and refraction, qt, respectively.

The refractive index of medium 1 is n1 and of medium 2 is n2. From this, it is easy to see that the angle of incidence and the angle of reflection are the same! If the angle of incidence is increased beyond that angle, then refraction does not occur! The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Asked 4 years, 5 months ago. Active 4 years, 5 months ago.

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