Question

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

• A. Refraction
• B. Diffraction
• C. Total Internal Reflection
• D. Interference

Hint:

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.

Answer 1

The Correct Option is C

Concept: Optical fibers transmit light signals over long distances using the principle of Total Internal Reflection (TIR). Total internal reflection occurs when light travels from a denser medium to a rarer medium and the angle of incidence is greater than the critical angle.

Step 1: Structure of optical fiber. An optical fiber consists of:
• Core (denser medium)
• Cladding (rarer medium)

Step 2: Propagation of light. Light entering the core undergoes repeated total internal reflections at the boundary between the core and cladding.

Step 3: Result. Because of continuous total internal reflection, the light signal travels through the fiber with very little loss.