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प्रश्न
- Assertion (A): Propagation of light through an optical fibre is due to total internal reflection taking place at the core-cladding interface.
- Reason (R): Refractive index of the material of the cladding of the optical fibre is greater than that of the core.
पर्याय
If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
If Assertion is true but Reason is false.
If both Assertion and Reason are false.
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उत्तर
If Assertion is true but Reason is false.
Explanation:
Propagation of light through an optical fibre is due to total internal reflection taking place at the core-cladding interface. The claim is correct.
One requirement for total internal reflection is that light goes from a denser to a rarer medium. Total internal reflection occurs in optical fibre as light passes from the core to the cladding. As a result, the core's refractive index should be larger than that of the cladding. As a result, the reason is untrue.
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संबंधित प्रश्न
State the conditions required for total internal reflection of light to take place
A light ray does not bend at the boundary in passing from one medium to the other medium if the angle of incident is ______.
Swarali has got the following observations while doing an experiment. Answer her questions with the help of observations.
Swarali observed that the light bent away from the normal, while travelling from dense medium to rarer medium. When Swarali increased the values of angle of incidence (i), the values of angle of refraction (r) went on increasing. But at a certain angle of incidence, the light rays returned into the dense medium.
So, Swarali has some questions. Answer them –
a) Name this certain value of ‘i ’. What is the value of ‘r’ at that time ?
b) Name this process of returning of light in dense medium. Explain the process.
Answer the following question.
Under what conditions are total internal reflection possible? Explain it with a suitable example.
Solve Numerical example.
A monochromatic ray of light is incident at 37° on an equilateral prism of refractive index 3/2. Determine angle of emergence and angle of deviation. If angle of prism is adjustable, what should its value be for emergent rays to be just possible for the same angle of incidence?
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°
For a ray of light, the critical angle is minimum when it travels from ______.
Total internal reflection can take place only if light is travelling from ______.
What are the conditions to achieve total internal reflection?
What is a mirage? How does it occur?
