Pick out the correct staments about optical fibres from the following: S1: Optical fibres are used for the transmission of optical signals only S2: Optical fibres are used for transmission of optical electrical signals S3: The intensity of light signals sent through optical fibres suffer very small loss S4: Optical fibres effectively employ the principle of multiple total internal reflections S5: Optical fibres are glass fibres coated with a thin layer of a material with lower refractive index
