Total internal reflection

Definition

Total internal reflection occurs when a light wave traveling through a denser medium hits the boundary with a less dense medium at an angle greater than the critical angle, causing the wave to be completely reflected back into the denser medium. This phenomenon is critical in fiber optics and certain optical instruments.

5 Must Know Facts For Your Next Test

1. Total internal reflection only occurs when light travels from a medium with a higher refractive index to one with a lower refractive index.
2. The critical angle is dependent on the refractive indices of the two media involved.
3. At angles greater than the critical angle, no refracted ray is observed; instead, all light is reflected back into the original medium.
4. Fiber optic cables utilize total internal reflection to transmit data over long distances with minimal loss.
5. Mirage effects in deserts are an example of total internal reflection.

Review Questions

• What conditions must be met for total internal reflection to occur?
• How does the critical angle relate to the refractive indices of two media?
• Explain why total internal reflection is essential for fiber optic technology.

Related terms

Critical Angle:

The minimum angle of incidence at which total internal reflection occurs when light passes from a denser to a less dense medium.

Refractive Index:

A dimensionless number that describes how fast light travels through a material compared to vacuum. It determines how much light bends when entering or exiting a material.

Snell's Law:

$n_1 \sin\theta_1 = n_2 \sin\theta_2$, where $n$ represents refractive indices and $\theta$ represents angles of incidence and refraction. It governs how light rays bend when passing between different media.