Mirage is an optical illusion observed in hot deserts. It is entirely caused by:
A. Scattering of light
B. Interference of light
C. Total internal reflection of light
D. Diffraction of light
Answer: Option C
Solution (By JKSSB Mock Tests)
In hot deserts, the sand heats the air immediately above it, making it less dense (optically rarer) than cooler air higher up. Light from a tall object (like the sky or a tree) traveling downwards passes from denser to rarer air layers, bending away from the normal. Eventually, the angle of incidence exceeds the critical angle, causing total internal reflection. The observer perceives this reflected light as a pool of water on the ground.
Explanation:
Volume V = a³. For error propagation: % error in V = 3 × % error in a. Given 2% error in side, volume error = 3×2% = 6%. Power rule: if Q = xⁿ, %ΔQ = |n|×%Δx. Memory tip: Volume depends on cube of length ⇒ errors triple. Common in experimental error analysis questions.
Explanation:
Optical fibers consist of a central core surrounded by a cladding with a slightly lower refractive index. When a light beam enters the core at an angle greater than the critical angle, it undergoes multiple successive total internal reflections against the core-cladding boundary. This allows the light to travel over vast distances with virtually no loss of energy, making it ideal for telecommunications.
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