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(f) Thick coaxial cable has an extra protective plastic cover that helps keep moisture away.

(g) It is relatively inexpensive as compared to fibre optic cable.
Disadvantages of Coaxial Cable

(a) Thick coaxial cables do not bend easily and thus are difficult to install.

(b) It is expensive as compared to twisted pair cable.
3. Fibre Optic Cable

Fibre optic transmits light signals rather than electrical signals. It is the newest form of guided
media. Several glass fibres are bundled together and are encased in an insulated covering. Light
signals travel into the fibre optic cable at one end and are received at the other end. When the light
enters the fibre optic, the light pulse inside the cable hits the outer walls of the wire at a similar
angle, which helps in moving the light wave forward. The outer surface of the glass wire provides
just the right angle reflection to keep the light bouncing back and forth along the length of cable.
The light source used in this process is light emitting diode (LED).
Optical fibres may be single mode or multimode. Single mode optic fibre transmits only single light
width but multimode fibre uses multiple light paths.

Cladding

Total internal
occurs here

Fig. 8.28: Fibre Optic Cable

Advantages of Fibre Optic

(a) Fibre optic typically offers better bandwidth and can carry more information at once.
(b) As the signal travels in the form of light, there is less attenuation and signal degradation.

(c) Optical fibre wires are made of glass, so there is little risk of fire because of absence of spark
hazards.
(d) Fibre optic cables are much thinner and lighter than metal wires.
(e) Lighter weight makes fibre easier to install.

(f) It does not leak signals, so it is immune to eavesdropping.
Computer Science with Python–XII 8.26 Disadvantages of Fibre Optic
(g) A signal can run for 50 km without requiring regeneration.

(h) Fibre optic cables are also used in research and development.

(a) A highly skilled labour is required for its installation and maintenance.

(b) It is relatively expensive as compared to other guided media.
(c) As fibre optic is made of glass, they can be easily broken.

(d) As light travels in a straight line, two fibres are needed if we need bidirectional
communication.