Optical Fibres
2 marks · NormalDescribe the main structure of an optical fibre. Name the two main parts and their roles.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
Also accept: core and cladding; core with higher refractive index, cladding with lower refractive index; core transmits light, cladding keeps light in
Common mistakes: Mixing up which layer has the higher refractive index
Show mark scheme and worked solution
Marking points
B1 · 1 mark · States the core and cladding as the two main parts (by name or description).
B1 · 1 mark · Identifies core has a higher refractive index (or cladding lower); or correctly describes their roles (core transmits light, cladding keeps light in).
Worked solution
An optical fibre consists of a core (central part) made of glass with a high refractive index and an outer cladding of glass with a lower refractive index. The core transmits the light, while the cladding keeps the light in the core by total internal reflection.