Question

Fibre optic cables transmit large amounts of data using .

• A. light
• B. water
• C. sound
• D. None of the above

Hint:

Think about what a fibre optic cable is physically made of and how it carries a signal.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The question is about the physical signal that carries information inside a fibre optic cable.

Step 2: Key Approach:
A fibre optic cable is built as a thin core of glass or plastic surrounded by a cladding layer with a lower refractive index. This structure is designed to trap and guide one particular kind of wave along its length.

Step 3: Detailed Explanation:
When a beam of light enters the core at the right angle, it keeps bouncing off the boundary between the core and the cladding through total internal reflection, instead of escaping outward.
This lets the light pulse, which is switched on and off very fast to represent data bits, travel long distances with very little signal loss.
Water and sound are not used because neither can be guided efficiently through a solid glass fibre the way light can, and plain electrical signals face far more resistance and interference over long cable runs than light does.

Step 4: Final Answer:
Since data in a fibre optic cable is carried as pulses of light guided by total internal reflection, the correct option is light, answer (a).