Now a days optical fibers are extensively used for transmitting audio and video signals through long distances. The optical fibers work on
Answer & explanation
Correct answer: option 3
Optical fibres work on the principle of total internal reflection(T.I.R).Total internal reflection is a complete reflection of a ray of light within a medium such as optical fibre from the surrounding surfaces back into the medium. The phenomenon occurs if the angle of incidence is greater than a certain limiting angle, called the critical angle.