Q. Which among the following is used to transmit data in optical fibre?
Answer: Light
Notes: Fiber optics, or optical fiber, refers to the medium and the technology associated with the transmission of information as light pulses along a glass or plastic strand or fiber. It cables carry information between two places using entirely optical (light-based) technology. The light signals do not travel at the speed of light because of the denser glass layers, instead traveling about 30% slower than the speed of light.