question_answer

The principle used for the transmission of light signals through the optical fibre is

A)  reflection          

B)  refraction

C)  interference                    

D)  diffraction

E)  total internal reflection

Correct Answer: E

Solution :

                The optical fibre consists of three parts (i) Central core made of glass or plastic. (ii) Central core is surrounded by cladding, a material of refractive index less than that of central core. (iii) Cladding is surrounded by an insulating jacket called protective jacket. When light enters the central core and incident on the interface of central core and cladding at an angle greater -than critical angle, total internal reflection tqkes place. This process is repeated again and again and light propagates through optical fibre. Therefore, the transmission of light signals through the optical fibre is based on the principle of total internal reflection.