The phenomenon of diffraction limits the resolving power of optical instruments because:
A. Light bends around edges, causing image blurring
B. Mirrors reflect imperfectly
C. Lenses absorb light
D. Atmospheric turbulence distorts light
Answer: Option A
Solution (By JKSSB Mock Tests)
Diffraction causes light waves to spread when passing through apertures or around obstacles, creating Airy patterns instead of point images. This fundamental wave effect limits the minimum resolvable detail (Rayleigh criterion: θ_min ≈ 1.22λ/D). Options B, C, D are practical limitations but not the fundamental diffraction limit. Memory tip: 'Diffraction limit: smaller λ or larger aperture ⇒ better resolution'. This wave optics concept is frequently tested in competitive exams. Always distinguish fundamental limits (diffraction) from technical limitations (aberrations, turbulence) in instrument performance.
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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