Advertisements
Advertisements
प्रश्न
Describe the construction and working of an optical fibre.
Advertisements
उत्तर
Construction:
- An optical fibre consists of an extremely thin, transparent, and flexible core surrounded by an optically rarer flexible cover called cladding.
- For protection, the whole system is coated by a buffer and a jacket
- The entire thickness of the fibre is less than half an mm.
- Many such fibres can be packed together in an outer cover.
Construction of Optical fiber
Working:
- Working of optical fibre is based on the principle of total internal reflection.
- An optical signal (a ray of light) entering the core suffers multiple total internal reflections before emerging out after several kilometres.
- The optical signal travels with the highest possible speed in the material.
- The emerged optical signal has an extremely low loss in signal strength.
Working of Optical fibre
APPEARS IN
संबंधित प्रश्न
The figure shows a ray of light falling normally on the face AB of an equilateral glass prism having refractive index`3/2`, placed in water of refractive index `4/3`.Will this ray suffer total internal reflection on striking the face AC? Justify your answer.
State the relation between the critical angle and the absolute refractive index of a medium.
What is total internal reflection?
Solve the previous problem if the paperweight is inverted at its place so that the spherical surface touches the paper.
(i) Define critical angle.
(ii) State one important factor which affects the critical angle of a given medium.
Plot a graph between
Angle of incidence versus angle of refraction.
How does a ray of light bend when it travels from denser to rarer medium.
How are critical angles related to the refractive index of the medium?
Images formed by totally reflecting prisms are brighter than the image formed by ordinary reflected light, why?
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’.
How is the angle of emergence ‘e’ related to the angle of incidence ‘i’?
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 ray of light passes through a right-angled prism as shown in the figure. State the angles of incidence at the faces AC and BC.
Answer the following question.
Why is prism binoculars preferred over traditional binoculars? Describe its working in brief.
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?
A green light is incident from the water to the air-water interface at the critical angle (C). Select the correct statement.
Total internal reflection can take place only if light is travelling from ______.
The twinkling effect of star light is due to ______.
The outer concentric shell in optic fiber is called ______.
What are the conditions to achieve total internal reflection?
What is a mirage? How does it occur?
Write any two uses of total internal reflection.
The phenomena involved in the reflection of radiowaves by ionosphere is similar to ______.
A jar of height h is filled with a transparent liquid of refractive index µ (Figure). At the centre of the jar on the bottom surface is a dot. Find the minimum diameter of a disc, such that when placed on the top surface symmetrically about the centre, the dot is invisible.
State the condition under which total internal reflection occurs. Give the mathematical expression for total internal reflection.
Observe the given figure of the raindrop and answer the following questions:
- Label A and B of the given diagram. Why colour will deviate most.
- Name the phenomenon shown in label C.
A ray of light passes through a prism of refractive index `sqrt2` as shown in the figure. Find:
- The angle of incidence (∠r2) at face AC.
- The angle of minimum deviation for this prism.
Small air bubbles rising up a fish tank appear silvery when viewed from some particular angle is due to the ______.
Name any two phenomena which take place in the formation of a rainbow.
