What are the shards of glass in fibre optic cables used for?

The shards of glass in fiber optic cables serve the primary purpose of reflecting pulses of light. Fiber optic cables utilize light to transmit data, and the glass fibers are designed to guide this light through the core of the cable via total internal reflection. This means that as light signals travel along the fiber, they bounce off the walls of the glass without escaping, enabling the efficient transmission of data over long distances. This property is crucial for maintaining the integrity and speed of the signals, as the reflections minimize loss and distortion, ensuring that the information reaches its destination with high fidelity.

In contrast, the other options involve functionalities that are not applicable to the role of glass in fiber optics. Conducting electricity is relevant to metallic wiring, while reducing noise pertains more to electrical signal transmission rather than optical. Insulating signals typically refers to preventing interference in electrical cables and is not a function of the glass used in fiber optics.