In multimode step index fibre the refractive index of core and cladding is____________?
Correct answer: D. different with refractive index of core higher than cladding
- A. same
- B. different
- C. zero
- D. different with refractive index of core higher than cladding
Explanation
A step-index fibre has a sudden change in refractive index at the core-cladding boundary, so the core and cladding have different refractive indices. For total internal reflection, the core index must be greater than the cladding index, ncore > ncladding. The likely mistake is choosing b, which recognizes only that the indices differ but misses the required order.
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Light is studied through reflection, refraction, dispersion, interference, diffraction and polarization, linking ray behavior with its wave nature. Questions may involve mirrors, lenses, optical instruments, refractive index and image formation, while geometrical optics deals with rays and wave optics explains effects such as interference and diffraction.
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