Concept:Total internal reflection occurs when light travels from a denser to a rarer medium at an angle greater than the critical angle. We need to identify which phenomenon does NOT depend on this principle.
Explanation:Let me analyze each option:
A. Working of optical fibre:Light travels through the core (denser medium) and undergoes total internal reflection at the core-cladding boundary, allowing light to propagate over long distances. ✓ Due to TIR
B. Difference between apparent and real depth of a pond:When viewing objects underwater from above, light refracts (bends) at the water-air interface as it exits the water. This refraction makes the pond appear shallower than it actually is. This is a
refraction phenomenon, not total internal reflection. ✗ NOT due to TIR
C. Mirage on hot summer days:Hot air near the ground has lower density (acts like a rarer medium). Light from the sky undergoes total internal reflection at the boundary between hot and cool air layers, creating the illusion of water. ✓ Due to TIR
D. Brilliance of diamond:Diamonds have a very high refractive index (~2.42). Light entering a diamond undergoes multiple total internal reflections before exiting, trapping light inside and making it sparkle brilliantly. ✓ Due to TIR
Answer:B. Difference between apparent and real depth of a pondThe apparent depth is caused by
refraction at the water-air interface, not total internal reflection.
