Which of the following is NOT a part of a fiber optic cable?

A fiber optic cable is primarily composed of materials that facilitate the transmission of light signals. The glass core is where the light propagates, allowing for the transmission of data over long distances with minimal loss. Surrounding the core, there is typically a cladding layer made of a different type of glass that reflects the light back into the core, ensuring it stays within the core and continues to transmit efficiently.

The protective silicone coating serves to shield the delicate glass core from environmental factors and physical damage, while the outer jacket protects the entire assembly from abrasions and impacts.

In contrast, a metal sheath is not a standard component of fiber optic cables. They are generally designed to be lightweight and composed of non-metallic materials that help to minimize weight and maintain flexibility. Fiber optic cables do not require electrical shielding, which is often found in traditional copper cables. Therefore, the inclusion of a metal sheath would be atypical and unnecessary for the operation of fiber optic technology. This distinction highlights why the option identifying a metal sheath as part of the cable is inaccurate.