Question:medium

The working of an optical fiber is based on which phenomenon?

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For total internal reflection to occur: 1. Light must travel from denser to rarer medium. 2. Angle of incidence must be greater than the critical angle.
Updated On: Apr 22, 2026
  • Refraction
  • Diffraction
  • Total Internal Reflection
  • Interference
Show Solution

The Correct Option is C

Solution and Explanation

Step 1: Understanding the Question:
Optical fibers are used to transmit light signals over long distances. The question asks for the physics principle that allows light to stay trapped inside the fiber.
Step 2: Detailed Explanation:
An optical fiber consists of a "Core" surrounded by a "Cladding".
The refractive index of the core (\(n_1\)) is greater than the refractive index of the cladding (\(n_2\)).
When light enters the core at an angle greater than the critical angle, it does not pass into the cladding.
Instead, it reflects back into the core. This process repeats along the length of the fiber.
This phenomenon is known as Total Internal Reflection (TIR).
Step 3: Final Answer:
The working principle is Total Internal Reflection.
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