Optical Fibre

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

An optical fibre is made of glass fibre of refractive index 1.68. The outer coating of the glass fibre is made of material of refractive index 1.44. What is the range of angles of the incident rays with the axis of the pipe for which total internal reflection inside the optical fibre takes place?

What are optical fibers ? Give three appilications of these fibres.