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प्रश्न
Answer the following question.
What are the advantages of optical fibre communication over electronic communication?
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उत्तर
Advantages:
- Broad bandwidth (frequency range): For TV signals, a single optical fibre can carry over 90000 independent signals (channels).
- Immune to EM interference: Optical fibre being electrically non-conductive, does not pick up nearby EM signals.
- Low attenuation loss: loss being lower than 0.2 dB/km, a single long cable can be used for several kilometres.
- Electrical insulator: Optical fibres being electrical insulators, ground loops of metal wires or lightning do not cause any harm.
- Theft prevention: Optical fibres do not use copper or other expensive material which are prone to be robbed.
- Security of information: Internal damage is most unlikely to occur, keeping the information secure.
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संबंधित प्रश्न
The diagram below shows a point source P inside a water container. Four rays A, B, C, D starting from the source P are shown up to the water surface
1) Show in the diagram the path of these rays after striking the water surface.
The Critical Angle for the water-air surface is 48°.
2) Name the phenomenon which the rays B and D exhibit.
State two conditions necessary for total internal reflection to occur.
In the given figure PQ and PR are the two light rays emerging from an object P. The ray PQ is refracted as QS.
- State the special name given to the angle of incidence ∠PQN of the ray PQ.
- What is the angle of refraction for the refracted ray QS?
- Name the phenomenon that occurs if the angle of incidence ∠PQN is increased.
- The ray PR suffers partial reflection and refraction on the water-air surface. Give reason.
- Draw in the diagram the refracted ray for the incident ray PR and hence show the position of image of the object P by the letter P’ when seen vertically from above.
Calculate the speed of light in a medium whose critical angle is 30° ?
Plot a graph between
Angle of incidence versus angle of reflection,
Name the principle on the basis of which optical fibres work.
Why do diamonds sparkle?
Write down the relationship between the critical angle and the refractive index of the medium.
If a ray of light passes from medium I to medium II without any change of direction, what can be said about the refractive indices of these media (angle I is not 0)?
A ray of light incident at an angle of incidence ‘i’ passes through an equilateral glass prism such that the refracted ray inside the prism is parallel to its base and emerges from the prism at an angle of emergence ‘e’.
What can you say about the value of the angle of deviation in such a situation?
How is the critical angle of a material related to its refractive index?
A spherical marble, of refractive index 1.5 and curvature 1.5 cm, contains a tiny air bubble at its centre. Where will it appear when seen from outside?
Choose the correct option.
Select the WRONG statement.
Explain ‘mirage’ as an illustration of refraction.
Answer the following question.
Under what conditions are total internal reflection possible? Explain it with a suitable example.
Answer the following question.
Define the critical angle of incidence and obtain an expression for it.
Describe the construction and working of an optical fibre.
Solve Numerical example.
From the given data set, determine angular dispersion by the prism and dispersive power of its material for extreme colours. nR = 1.62 nV = 1.66, δR = 3.1°
Which one of the following is NOT the correct formula for refractive index of glass w.r.t. air (aμg) (i = angle of incidence, r = angle of refraction)
The outer concentric shell in optic fiber is called ______.
Which of the following statements about total internal reflection is true?
The critical angle is defined as the angle of incidence at which the total internal reflection starts to occur.
Optical Fibres are based on the phenomenon of dispersion.
The angle of incidence at which the angle of refraction is Q£ is called the critical angle.
What is a mirage? How does it occur?
State two differences between normal reflection and total internal reflection.
