Optical Communication - Study Mode

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[#146] If a light travels in a certain medium and it gets reflected off an optically denser medium with high refractive index, then it is regarded as . . . . . . . .

(A) External Reflection

(B) Internal Reflection

(C) Both A and B

(D) None of the above

Correct Answer

(A) External Reflection

[#147] In a optical fiber, the refractive index of the cladding material should be

(A) nearly unity

(B) very low

(C) less than that of the core

(D) more than that of the core

Correct Answer

(C) less than that of the core

[#148] . . . . . . . . is used to describe the light gathering or light collecting ability of an optical fiber

(A) Critical angle

(B) Cut-off wavelength

(C) Numerical Aperture

(D) Acceptance angle

Correct Answer

(C) Numerical Aperture

[#149] A step index fibre has core diameter 40 µm with core refractive indix of 1.3 and numerical aperture 0.5, then the refractive index of cladding is

(A) 1.2

(B) 1.1

(C) 0.9

(D) 0.8

Correct Answer

(A) 1.2

[#150] Refractive index of glass is 1.5. What is the wavelength of a beam of light with a frequency of 10 14 Hz in glass? Assume velocity of light in vacuum to be 3 × 10 8 m/sec.

(A) 3 µm

(B) 3 mm

(C) 2 µm

(D) 1 µm

Correct Answer

(C) 2 µm