everyday science MCQ #50901

Optical fibres in telecommunications carry data as pulses of light over thousands of kilometres with minimal signal loss. Which optical phenomenon keeps the light confined within the fibre?

everyday science MCQ #50901

  1. Question 1

    Q1. Optical fibres in telecommunications carry data as pulses of light over thousands of kilometres with minimal signal loss. Which optical phenomenon keeps the light confined within the fibre?

    • A) Polarisation — light is oriented in one plane so it cannot escape through the fibre walls
    • B) Total internal reflection — light strikes the fibre wall at an angle beyond the critical angle and reflects entirely back inward
    • C) Diffraction — light bends around the curved fibre walls and stays within the core
    • D) Constructive interference — light waves reinforce each other and cannot escape

    Answer: Total internal reflection — light strikes the fibre wall at an angle beyond the critical angle and reflects entirely back inward

    Explanation: Total internal reflection occurs when light travelling inside a denser medium strikes the boundary with a less dense medium at an angle greater than the critical angle, causing all the light to reflect back inward rather than refracting out.