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Explain briefly how the phenomenon of total internal reflection is used in fibre optics. |
Answer» Solution :Optical fibres CONSIST of MANY, long high quality composite glass/quartz fibres. Each fibre consists of a core of high refractive index and a cladding of lower refractive index. Optical fibre works on the principle of total internal Core (high N) reflection. When a light signal is INCIDENT on one end of the fibre at a small angle, the light passes inside, undergoes repeated total internal reflections along the fibre and finally comes out as shown in Fig. 9.56. The angle of incidence isCladding (low n) ALWAYS greater than the critical angle of the core material 9-56 with respect to the cladding. Even if the fibre is bent, the light signal can easily travel through along the fibre.
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