Question

Which of the following is not due to total internal reflection?

• A. Working of optical fibre
• B. Difference between apparent and real depth of a pond
• C. Mirage on hot summer days
• D. Brilliance of diamond

Answer 1

The Correct Option is B

Total internal reflection is a phenomenon that occurs when a wave, such as light, hits a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface. At this angle, all the wave is reflected and none of it is refracted. Let's explore which options are related to total internal reflection:

1. Working of optical fibre: Optical fibers use total internal reflection to transmit light over long distances. The light is repeatedly reflected within the core of the fiber, allowing it to travel with minimal loss. Hence, this is due to total internal reflection.
2. Difference between apparent and real depth of a pond: This phenomenon is due to the refraction of light, not total internal reflection. Light bends as it moves from water to air, making the pond appear shallower than it actually is. Therefore, this option is not caused by total internal reflection.
3. Mirage on hot summer days: A mirage is an optical phenomenon where light rays are bent to produce a displaced image of distant objects or the sky. This is a result of total internal reflection within layers of air of differing temperatures and densities.
4. Brilliance of diamond: Diamonds exhibit exceptional brilliance due to the total internal reflection of light that enters them. The light is internally reflected multiple times before exiting, which gives diamonds their sparkle.

Therefore, the phenomenon among the given options that is not due to total internal reflection is the Difference between apparent and real depth of a pond.