Irrespective of the size of the optical fibre, light travels in it because it is a device through which signals can be transferred from one place to another. On which phenomenon is this based?

Light travels in optical fibers due to total internal reflection of light (option D). Total internal reflection is a phenomenon where light, upon encountering the boundary between two materials with different refractive indices, is reflected back into the denser material if it strikes the boundary at an angle greater than the critical angle. In optical fibers, which are typically made of a core surrounded by cladding with lower refractive index, light entering the core at an angle greater than the critical angle undergoes total internal reflection. This continuous reflection allows light to propagate through the fiber by bouncing off the core-cladding interface, even if the fiber bends. This property of total internal reflection enables optical fibers to transmit signals over long distances with minimal loss and interference. Unlike diffraction (option A), refraction (option B), or polarization (option C), total internal reflection is the specific optical phenomenon that facilitates the efficient transmission of light signals through optical fibers.